Canadian Researchers Link DICER1 Gene Mutation to Non-Epithelial Ovarian Cancers & Other Rare Tumor Types

Canadian researchers affiliated with the Ovarian Cancer Research Program of British Columbia report that recurrent, lifetime-acquired mutations affecting the DICER1 gene occur in a range of nonepithelial ovarian tumors as well as other rare cancer tumor types, and appear common in Sertoli-Leydig ovarian tumors. The study findings were published online today in the New England Journal of Medicine.

Dr. Gregg Morin, Head of Proteomics, Michael Smith Genome Sciences Centre, BC Cancer Agency; DICER 1 Mutation Ovarian Cancer Study Co-Leader

Dr. David Huntsman, Genetic Pathologist & Director of the Ovarian Cancer Research Program of British Columbia at the BC Cancer Agency & Vancouver Coastal Health Research Institute; DICER 1 Mutation Ovarian Cancer Study Co-Leader

Scientists at the British Columbia (BC) Cancer Agency, Vancouver Coastal Health Research Institute, and the University of British Columbia (UBC) are excited over a discovery made while studying rare tumor types.

Dr. David Huntsman, genetic pathologist and director of the Ovarian Cancer Program of BC (OvCaRe) at the BC Cancer Agency and Vancouver Coastal Health Research Institute, and Dr. Gregg Morin, a lead scientist from the Michael Smith Genome Sciences Centre at the BC Cancer Agency, led a research team who discovered that mutations in rare, seemingly unrelated cancers were all linked to the same gene, known as “DICER1.” The study findings were published online today in the New England Journal of Medicine. [1]

Background: RNA Interference, MicroRNAs, and DICER.

Nucleic acids are molecules that carry genetic information and include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). The DNA segments that carry genetic information are called “genes.” Together these molecules form the building blocks of life. DNA contains the genetic code or “blueprint” used in the development and functioning of all living organisms, while “messenger RNAs” or mRNAs help to translate that genetic code into proteins by acting as a messenger between the DNA instructions located in the cell nucleus and the protein synthesis which takes place in the cell cytoplasm (i.e., outside the cell nucleus, but inside the outer cell membrane). Accordingly, DNA is first “transcribed” or copied into mRNA, which, in turn, gets “translated” or synthesized into protein.

RNA interference” (RNAi) is a mechanism through which gene expression is inhibited at the translation stage, thereby disrupting the protein production within a cell. RNAi is considered one of the most important discoveries in the field of molecular biology. Andrew Fire, Ph.D., and Craig C. Mello, Ph.D. shared the 2006 Nobel Prize in Physiology or Medicine for work that led to the discovery of the RNAi mechanism. While the mechanism itself is termed “RNA interference,” there are two major types of RNA molecules that play a key role in effectuating that interference. The first type of RNA molecules consists of “microRNAs” or miRNAs, while the second type consists of “small interfering RNAs” or siRNAs.

Current thinking suggests that RNAi evolved as a cellular defense mechanism against invaders such as RNA viruses. When they replicate, RNA viruses temporarily exist in a double-stranded form. This double-stranded intermediate would trigger RNAi and inactivate the virus’ genes, thereby preventing viral infection. RNAi may also have evolved to combat the spread of genetic elements called “transposons” within a cell’s DNA. Transposons can wreak havoc by jumping from spot to spot on a genome, sometimes causing mutations that can lead to cancer or other diseases. Like RNA viruses, transposons can take on a double-stranded RNA form that would trigger RNAi to clamp down on the potentially harmful “jumping gene” activity. Also, as noted above, RNAi is important for regulating gene expression. For example, the turning down of specific genes is critical to proper embryonic development.

Of relevance to the Canadian study findings within the context of RNAi are miRNAs. MiRNAs can bind to mRNAs and either increase or decrease their activity, for example, by preventing a mRNA from producing a protein. [2] In this context, “gene silencing” can occur through mRNA degradation or prevention of mRNA translation.  MiRNAs play an integral role in numerous biological processes, including the immune response, cell-cycle control, metabolism, viral replication, stem cell differentiation and human development. MiRNA expression or function is significantly altered in many disease states, including cancer.

Because of its involvement in miRNA processing, the DICER1 gene plays an important role in maintaining health. It carries out a “factory style” function which involves chopping up miRNAs to activate them. [Ref. 2] These miRNAs, in turn, control hundreds of other genes as noted above. Based upon a study led by investigators from the University of Texas M.D. Anderson Cancer Center, the expression levels of DICER have global effects on the biogenesis of miRNA, and reduced gene expression correlates with a poor outcome in ovarian cancer. [3] In the M.D. Anderson study, two somatic (i.e., lifetime-acquired) missense DICER mutations were discovered in two epithelial ovarian cancer tumors. The M.D. Anderson investigators concluded that the DICER mutations were not associated with the alterations in DICER expression found in mRNAs. It is important to note that the type of somatic missense DICER mutations discovered in the M.D. Anderson study were not the same as those discovered in the Canadian study as discussed below.

Recurrent DICER Mutations Are Predominant In A Rare Form of Non-Epithelial Ovarian Cancer.

At the outset of the Canadian study, the OvCaRe team sequenced ovarian, uterine, and testicular tumors, expecting to find that their genomes would be distinct with specific, differing abnormalities. Much to their amazement, the researchers discovered that the same fundamental mutation in the DICER1 gene represented a common process underlying the different cancers which they examined.

Specifically, the Canadian investigators sequenced the whole transcriptomes or exomes of 14 nonepithelial ovarian tumors, which included two Sertoli–Leydig cell tumors, four juvenile (not adult) granulosa-cell tumors, and eight primitive germ-cell tumors of the yolk-sac type. The researchers identified closely clustered mutations in the region of DICER1 which encode the RNase IIIb domain in four samples. Based on these findings, the OvCaRe team sequenced the same region of DICER1 in additional ovarian tumors, and tested for the effect of the mutations on the enzymatic activity of DICER1.

Recurrent somatic (i.e., lifetime-acquired) DICER1 mutations in the RNase IIIb domain were identified in 30 of 102 nonepithelial ovarian tumors (29%), including 4 tumors which also possessed germline (i.e., inherited) DICER1 mutations. The highest frequency of somatic DICER1 mutations occurred in Sertoli–Leydig cell tumors (26 of 43, or 60%). Notably, the mutant DICER1 proteins identified in the samples possessed reduced RNase IIIb activity, but retained RNase IIIa activity.

The Canadian researchers also performed additional tumor testing and detected the DICER1 mutations in 1 of 14 nonseminomatous testicular germ-cell tumors, 2 of 5 embryonal rhabdomyosarcomas, and in 1 of 266 epithelial ovarian and endometrial carcinomas.

The groundbreaking nature of this discovery is reflected in the fact that the DICER1 “hotspot” mutations are not present in the 1000 Genomes Project data or the public data repository of The Cancer Genome Atlas consortium. To date, no recurrent DICER1 mutations have been reported in the mutation database of the Catalogue of Somatic Mutations in Cancer (COSMIC), in which 4 of 938 reported cancers possess somatic mutations but none in the RNase IIIb domain hot spots or RNase IIIa equivalents. Moreover, the Canadian researchers note that the newly-discovered DICER1 mutations were not observed in any of the more than 1000 cancer sequencing libraries which were studied.

Based upon the foregoing , the researchers concluded that somatic missense mutations affecting the RNase IIIb domain of DICER1 occur in a range of nonepithelial ovarian tumors, and possibly other cancers. Furthermore, the DICER1 mutations appear to be common in Sertoli-Leydig ovarian tumors (which are a subtype of nonepithelial, sex cord-stromal ovarian tumors). The researchers believe that the recurrent DICER1 mutations identified implicate a novel defect in miRNA processing which does not entirely destroy DICER1 functionality, but alters it.

Accordingly, the Canadian researchers suggest that the newly-discovered DICER1 mutations may represent an oncogenic event within the specific context of nonepithelial ovarian tumors, rather than a permissive event in tumor onset (as may be expected for loss of function in a tumor suppressor gene). The researchers note that DICER1 expression in tumors possessing the hotspot DICER1 somatic mutations argues against a role for DICER1 as a classic tumor suppressor gene. They further explain that the localized and focal pattern of the identified DICER1 mutations is typical of dominantly acting oncogenes, like KRAS and BRAF.

In sum, the Canadian researchers believe that the recurrent and focal nature of the DICER1 mutations and their restriction to nonepithelial ovarian tumors suggest a common oncogenic mechanism associated with a specifically altered DICER1 function that is selected during tumor development in specific cell types.

The Canadian study was supported through funding by Canadian Institutes for Health Research, Terry Fox Foundation, BC Cancer Foundation, VGH & UBC Hospital Foundation, Michael Smith Foundation for Health Research, and Genome BC.

Expert Commentary

DICER is of great interest to cancer researchers” said Dr. Huntsman, who also holds the Dr. Chew Wei Memorial Professorship in the departments of Obstetrics and Gynecology and Pathology and Laboratory Medicine at UBC. “There have been nearly 1,300 published studies about it in the last 10 years, but until now, it has not been known how the gene functions in relation to cancer.”

“This discovery shows researchers that these mutations change the function of DICER so that it participates directly in the initiation of cancer, but not in a typical ‘on-off’ fashion,” says Dr. Morin who is also assistant professor in the department of Medical Genetics at UBC. “DICER can be viewed as the conductor for an orchestra of functions critical for the development and behavior of normal cells. The mutations we discovered do not totally destroy the function of DICER rather they warp it—the orchestra is still there but the conductor is drunk.”

This finding is the third of a series of papers published recently in the New England Journal of Medicine (NEJM) in which the OvCaRe team used new genomic technologies to unlock the molecular basis of poorly understood types of ovarian cancer. The first finding, published in the NEJM in 2009, identified mutations in the FOXL2 (forkhead box L2) gene as the molecular basis of adult granulosa cell ovarian cancer tumors. The second finding, published in the NEJM in 2010, determined that approximately one-half of clear-cell ovarian cancers and one-third of endometrioid ovarian cancers possess ARID1A  (AT rich interactive domain 1A) gene mutations.

The DICER gene mutation breakthrough discovery is particularly pivotal because it could lead to solutions for treatment of more common cancers.

“Studying rare tumors not only is important for the patients and families who suffer from them but also provides unique opportunities to make discoveries critical to more common cancers – both in terms of personalized medicine, but also in applying what we learn from how we manage rare diseases to more common and prevalent cancers,” said Dr. Huntsman “The discovery of the DICER mutation in this varied group of rare tumors is the equivalent of finding not the needle in the haystack, but rather the same needle in many haystacks.”

Dr. Phillip A. Sharp, Professor, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology; Co-winner of the 1993 Nobel Prize in Physiology and Medicine

“This breakthrough will be of interest to both the clinical and the fundamental science communities,” says Dr. Phillip A. Sharp, Professor, Koch Institute for Integrative Cancer Research at the Massachusetts Institute of Technology, and co-winner of the 1993 Nobel Prize in Physiology or Medicine for the discovery that genes are not contiguous strings but contain introns, and that the splicing of mRNA to delete those introns can occur in different ways, thereby yielding different proteins from the same DNA sequence. “Huntsman, Morin and colleagues’ very exciting discovery of specific mutations in DICER, a factor essential for syntheses of small regulatory RNAs in ovarian and other human tumors, could lead to new approaches to treatment.”

The Canadian OvCaRe research team is now working to determine the frequency and role of DICER mutations in other types of cancers. The research team is also expanding its collaboration to discover whether mutant DICER and the pathways it controls can be modulated to treat the rare cancers in which the mutations were discovered and more common cancers.

The Michael Smith Genome Sciences Centre (Michael Smith GSC), located at the BC Cancer agency, played a key role in this discovery. By way of background, Dr. Michael Smith was a co-winner of the 1993 Nobel Prize in Chemistry for his development of oligonucleotide-based site-directed mutagenesis, a technique which allows the DNA sequence of any gene to be altered in a designated manner. His technique created a groundbreaking method for studying complex protein functions, the basis underlying a protein’s three-dimensional structure, and a protein’s interaction with other molecules inside the cell.

A decision was made more than 10 years ago, championed by Drs. Michael Smith, Victor Ling, and others to create and locate the Michael Smith GSC within the BC Cancer Agency and in close proximity to Vancouver General Hospital (VGH). The chosen location for this critical facility provided the multidisciplinary cancer research teams in Vancouver with access to state-of-the-art technologies.

“We are one of less than five places in the world doing this type of work successfully. This discovery is one of a series of recent landmark findings from Vancouver that are reshaping our understanding of many cancers,” says Dr. Huntsman. “Since my arrival in Vancouver 20 years ago I have never before sensed such a strong feeling of communal pride and excitement within our research community. Our next task is to bring the discoveries into the clinic.”

About the Ovarian Cancer Research Program of British Columbia (OvCaRe)

OvCaRe is a multidisciplinary research program involving clinicians and research scientists in gynecology, pathology, and medical oncology at VGH and BC Cancer Agency. OvCaRe is a unique collaboration between the BC Cancer Agency, Vancouver Coastal Health Research Institute, and UBC. The OvCaRe team is considered a leader in ovarian cancer research which is breaking new ground in better identifying, understanding, and treating this disease. The OvCaRe seminal paper in PLoS (Public Library of Science), which addresses ovarian cancer as a group of distinct diseases, has been embraced by the global research community who has adopted the BC approach to ovarian cancer research. To learn more, visit www.ovcare.ca.

About the Michael Smith Genome Sciences Centre

Canada’s Michael Smith Genome Sciences Centre is an internationally recognized state-of-the-art facility applying genomics and bioinformatics tools and technologies to cancer research. Led by Dr. Marco Marra, the Michael Smith GSC is one of ten leading genomic research centres in the world and the only one of its kind in the world integrated into a cancer facility. With a primary focus on cancer genomics research, its scientists have been involved in many world-class groundbreaking discoveries over the past decade. To learn more, visit www.bcgsc.ca.

About the Vancouver Coastal Health Research Institute

Vancouver Coastal Health Research Institute is the research body of Vancouver Coastal Health Authority, which includes BC’s largest academic and teaching health sciences centres: Vancouver General Hospital, UBC Hospital, and GF Strong Rehabilitation Centre. The institute is academically affiliated with the UBC Faculty of Medicine, and is one of Canada’s top-funded research centres, with $82.4 million in research funding for 2009/2010. To learn more, visit www.vchri.ca.

About the British Columbia Cancer Agency

The BC Cancer Agency, an agency of the Provincial Health Services Authority, is committed to reducing the incidence of cancer, reducing the mortality from cancer, and improving the quality of life of those living with cancer. It provides a comprehensive cancer control program for the people of British Columbia by working with community partners to deliver a range of oncology services, including prevention, early detection, diagnosis and treatment, research, education, supportive care, rehabilitation and palliative care. To learn more, visit www.bccancer.ca.

About the University of British Columbia

The University of British Columbia is one of North America’s largest public research and teaching institutions, and one of only two Canadian institutions consistently ranked among the world’s 40 best universities. Surrounded by the beauty of the Canadian West, it is a place that inspires bold, new ways of thinking that have helped make it a national leader in areas as diverse as community service learning, sustainability, and research commercialization. UBC offers more than 55,000 students a range of innovative programs and attracts $550 million per year in research funding from government, non-profit organizations, and industry through 7,000 grants. To learn more, visit www.ubc.ca.

References

1/Morin G, Hunstman, DG et al.  Recurrent Somatic DICER1 Mutations in Nonepithelial Ovarian CancersNEJM, published online December 21, 2011 (10.1056/NEJMoa1102903).

2/The Canadian investigators describe the operation of the RNAi pathway with respect to miRNA biogenesis as follows:

“MicroRNAs (miRNAs) are a functional class of noncoding RNA molecules that regulate translation and degradation of messenger RNA. MiRNA transcripts are processed from hairpin pre-miRNA precursors into short miRNA:  miRNA* duplexes consisting of the miRNA targeting strand and the imperfectly complementary miRNA* strand (star strand, or inert carrier strand) by Dicer, an endoribonuclease with two RNase III–like domains. The RNase IIIb domain cuts the miRNA strand, whereas the RNase IIIa domain cleaves the miRNA* strand. The resultant RNA duplex is loaded into the RNA-induced silencing complex (RISC) containing an Argonaute protein. The miRNA* strand is then removed, leaving the miRNA strand, which targets messenger RNAs (mRNAs) for degradation or interacts with the translation initiation complex to inhibit and destabilize translation of the targeted messenger RNAs.” [footnote citations omitted]

3/Merritt WM, et al. Dicer, Drosha, and outcomes in patients with ovarian cancer. N Engl J Med. 2008 Dec 18;359(25):2641-50. Erratum in: N Engl J Med. 2010 Nov 4;363(19):1877. PubMed PMID: 19092150; PubMed Central PMCID: PMC2710981.

Sources:

2011 ASCO: Additional Phase III Study Data Support the Potential Role of Avastin in Newly-Diagnosed & Recurrent Ovarian Cancer

Positive results from two bevacizumab (Avastin®) phase III clinical studies were presented at the 2011 American Society of Clinical Oncology Annual Meeting on June 4. The data reported add to the growing body of evidence in support of bevacizumab use to treat recurrent and newly-diagnosed ovarian cancer.

Positive results from two bevacizumab (Avastin®) phase III clinical studies were presented at the 2011 American Society of Clinical Oncology Annual Meeting on June 4. The data reported add to the growing body of evidence in support of bevacizumab use to treat recurrent and newly-diagnosed ovarian cancer.

About Bevacizumab (Avastin®)

A diagram illustrating the role of the VEGF protein in the formation of new blood vessels that support tumor growth. Click on the picture above to view a video regarding the mechanism of action with respect to bevacizumab (Avastin®). (Photo: Genentech)

Angiogenesis” refers to the process of new blood vessel formation. When tissues need more oxygen, they release molecules that encourage blood vessel growth. Angiogenesis is a normal and vital process in human growth and development, as well as in wound healing. Unfortunately, cancer tumors also utilize this same process to enhance their own blood supply in order to nourish their aberrant growth.

Ovarian cancer is associated with high concentrations of vascular endothelial growth factor (VEGF), a protein associated with tumor growth and spread. Studies have shown a correlation between a high concentration of VEGF and ascites  (excess fluid in the body cavity) development, disease worsening, and a poorer prognosis in women with ovarian cancer.[1-2]

Bevacizumab is a humanized monoclonal antibody designed to specifically bind to the VEGF protein, which plays an important role throughout the lifecycle of the tumor to develop and maintain blood vessels through angiogenesis. The drug interferes with the tumor blood supply by directly binding to the VEGF protein to prevent interactions with receptors on blood vessel cells. The tumor blood supply is thought to be critical to a tumor’s ability to grow and spread in the body (metastasize).

Bevacizumab is the first U.S. Food and Drug Administration (FDA) approved therapy designed to inhibit angiogenesis. Although FDA-approved for several forms of cancer, bevacizumab is not yet approved for the treatment of ovarian cancer. Patients treated with bevacizumab may experience side effects. In past clinical trials, some people treated with bevacizumab experienced serious and sometimes fatal side effects, related to gastrointestinal (GI) perforation, surgery and wound healing, and severe bleeding. For more information, review the Avastin BOXED WARNINGS and Additional Important Safety Information.

OCEANS Phase III Clinical Study: Women with Recurrent Platinum Sensitive Ovarian Cancer Experience 78% Response Rate & 52% Reduction In Disease Progression Risk

  • About the OCEANS Study

“OCEANS” is a multicenter, randomized, double-blind, placebo-controlled Phase III study in 484 women with platinum drug-sensitive recurrent ovarian, primary peritoneal or fallopian tube cancer.[3] Women in the OCEANS study received no more than one treatment regimen prior to study enrollment.  The OCEANS study randomized enrolled women to one of two clinical study arms:

Arm A: Intravenous carboplatin (area under the curve (AUC) 4; Day 1) + gemcitabine  (1,000 mg/m2; Day 1 & 8; brand name: Gemzar®) + placebo (Day 1) every 21 days x 6 cycles, followed by placebo maintenance every 21 days, until disease progression or unacceptable toxicity occurred.

Arm B: Carboplatin + gemcitabine + bevacizumab (15 mg/kg; Day 1) every 21 days x 6 cycles, followed by single agent bevacizumab maintenance every 21 days, until disease progression or unacceptable toxicity occurred.

The primary endpoint of the OCEANS study was progression free survival. The secondary endpoints of the study included overall survival, objective response, duration of response and safety profile.

  • OCEANS Study Data

Carol Aghajanian, M.D. speaks during the Oral Abstract Session: Gynecologic Cancer at the American Society of Clinical Oncology Annual Meeting on Saturday June 4, 2011. (Photo: ASCO/GMG/Silas Crews 2011)

Carol Aghajanian, M.D., chief of the gynecologic medical oncology service at Memorial Sloan-Kettering Cancer Center, presented the data from the OCEANS study comparing efficacy and safety of chemotherapy and antiangiogenic therapy in platinum drug-sensitive recurrent ovarian cancer.

Two hundred forty-two women were allocated to each study arm and the median follow-up period was 24 months. Patient characteristics were well-matched in the two treatment groups with regard to age (median age ~60), race (~91% white), performance status (~75%, PS = 0), histologic subtype (~80% serous), cytoreductive surgery (~11%), and platinum-free interval (defined as the time between finishing front-line platinum-based therapy and starting second-line chemotherapy) of more than 12 months (~60%). The study stratification variables were platinum-free interval (6 to 12 months vs. more than 12) and cytoreductive surgery for recurrent disease (yes vs. no).

The median number of chemotherapy cycles was six for each group, and a median of 11 cycles of bevacizumab or placebo was given. At least one-third of the patients received more than six cycles of carboplatin and gemcitabine, although slightly more of the placebo-treated group continued chemotherapy beyond six cycles.

Progression-free survival was significantly longer for women given bevacizumab (12.4 months vs. 8.4 months in the placebo-treated group (hazard ratio [HR]: 0.484; 95% confidence interval (CI) [0.388, 0.605]; p < 0.0001). These results were corroborated by the analyses of an independent review committee. Analyses according to platinum-free interval, cytoreductive surgery, age, and baseline performance status indicate a consistent benefit in all subgroups.

Objective response rate increased by 21.1% (p < 0.0001), from 57.4% in the placebo group to 78.5% in the bevacizumab treated group; duration of response increased from a median of 7.4 months to 10.4 months, respectively (HR: 0.534; 95% CI [0.408, 0.698]; p < 0.0001). Overall survival data are still premature, with median survival of 29.9 months in the placebo group and 35.5 months in the bevacizumab treatment group.

Sixty-five percent of the patients in the placebo group were withdrawn from the protocol due to disease progression, compared with only 41% of the treatment group, but 23% of the discontinuations in the bevacizumab group were due to adverse events, compared with only 5% in the placebo group. Much of this increase was due to grade 3 (or worse) adverse events; specifically hypertension and proteinuria associated with bevacizumab therapy. Overall, the safety profile of bevacizumab was consistent with past trials.

  • OCEANS Study Commentary

Dr. Aghajanian concluded that the OCEANS study results demonstrate a statistically significant and clinically relevant benefit when bevacizumab is added to carboplatin and gemcitabine. Aghajanian stated that this regimen should be considered a new option for the treatment of recurrent, platinum drug-sensitive ovarian cancer. As expected, the rate of adverse events was higher among patients who received bevacizumab, explained Dr. Aghajanian. “Hypertension and proteinuria were increased, but febrile neutropenia was the same in both arms.” “The safety data are reassuring and consistent with the known bevacizumab side-effect profile, and there were no new safety signals,” said Dr. Aghajanian.

“In advanced ovarian cancer, just as in advanced breast cancer, there is often an opportunity to intervene with different lines of chemotherapy,” said Andrew Seidman, M.D., attending physician for the breast cancer medicine service at Memorial Sloan-Kettering Cancer Center and professor of medicine at Weill Medical College of Cornell University. “There are many chapters in the story, so to speak,” said Dr. Seidman, who moderated a press briefing held in advance of the presentation. “We want to prolong each and every chapter in the disease, and make the story longer and ultimately improve survival. These trials results are certainly an important step in that direction.”

“Women with recurrent ovarian cancer need new treatment options, and it is therefore an important advance to halve the risk of disease progression in this incurable cancer,” said Hal Barron, M.D., chief medical officer and head of Roche Holdings Global Product Development. “These data add to the growing body of evidence supporting Avastin’s potential role in this disease, which includes two previously presented Phase III clinical trials [Gynecologic Oncology Group (GOG)-218 [4] & ICON7] in women with newly diagnosed ovarian cancer.”

In his discussion of the study, Anil K. Sood, M.D., professor and director of the Blanton-Davis Ovarian Cancer Research Program in the Departments of Gynecologic Oncology and Cancer Biology at the University of Texas M.D. Anderson Cancer Center, suggested that further understanding of the timing and dosing of bevacizumab should be pursued in light of (i) its great financial cost, and (ii) reports that inhibition of angiogenesis in animal models reduces primary cancer tumor growth, but accelerates invasion and metastasis — unintended consequences that might be linked to the failure of bevacizumab to extend overall survival in most clinical trials.

ICON7 Phase III Clinical Study:  Newly-Diagnosed Women with High-Risk Ovarian Cancer Experience 36% Reduction in Risk of Death

Gunnar Kristensen M.D., Ph.D. speaks during the Women's Cancers Press Briefing at the American Society of Clinical Oncology Annual Meeting on June 4, 2011. (Photo: ASCO/GMG/Scott Morgan 2011)

ICON7 was designed to investigate safety and efficacy of adding bevacizumab to standard chemotherapy in women with newly diagnosed ovarian cancer. [5] Gunnar Kristensen, M.D, Ph.D., senior consultant in the Department for Gynecologic Oncology of the Norwegian Radium Hospital located in Oslo, reported the Phase III clinical study results.

  • About the ICON7 Study

From December 2006 to February 2009, 1,528 women were randomized from 263 centers in 7 Gynecologic Cancer InterGroups. Eligible women with high-risk early FIGO (Federation of International Gynecology and Obstetrics) stage I or IIa (grade 3 or clear cell histology), capped ≤10%) or advanced (stage IIb-IV) epithelial ovarian, primary peritoneal or fallopian tube cancer were randomizsed (1:1) to one of two study arms:

Arm A: 6 cycles of 3 weekly chemotherapy (carboplatin AUC 5 or 6 and paclitaxel 175mg/m2) alone;  or

Arm B: Same chemotherapy as in Arm A, given concurrently with bevacizumab (7.5mg/kg) for 5 or 6 cycles, followed by continued 3-weekly single-agent bevacizumab maintenance therapy for 12 additional cycles (up to 12 months) or until disease progression (whichever event occurs first).

The baseline patient characteristics were balanced between both study arms: median age (57 years); ECOG Performance Status 0-1 (47%); high-risk early-stage disease (9%); poor prognosis patients (30%); histology (69% serous, 8% endometrioid, 8% clear cell).

  • Updated ICON7 Progression Free Survival Data

Data from the ICON7 study were presented for the first time at the 2010 European Society of Medical Oncology (ESMO) Congress. As reported at ESMO, chemotherapy-naïve ovarian cancer patients who received bevacizumab in combination with standard chemotherapy, and then continued with single agent bevacizumab maintenance therapy, experienced approximately 27% improvement (18.3 months versus 16 months) in the likelihood of living longer without the disease worsening (i.e., progression-free survival) compared to those women who received only chemotherapy (hazard ratio = 0.79, p=<0.0010), which corresponds to a 21% reduction in risk of cancer progression or death. The ICON7 data presented at ESMO was based upon mature progression-free survival results.

The updated ICON7 progression-free survival data presented at the ASCO annual meeting were consistent with the data reported last year at ESMO. In the updated analysis, women assigned to the bevacizumab arm experienced longer progression-free survival than those in the control group (19.8 months vs 17.4 months; HR, 0.87; p =.039). “There is a substantial prolongation of time to progression,” said Dr. Kristensen, adding that the gain was 2.4 months.

  • ICON7 Overall Survival Data Immature; But Clear Benefit To Women With “Poor Prognosis.” 

At a median follow-up of 28 months, there were fewer deaths among women who received bevacizumab than among those who received standard chemotherapy (178 vs 200). Although this represents a 15% overall reduction in mortality risk, the difference did not reach statistical significance (hazard ratio [HR], 0.85; P = .11). The final analyses for overall survival will be performed when 715 patient deaths have occurred. The current analysis was conducted because an interim analysis with at least 365 deaths was requested by the FDA and the European Medicines Agency for licensing consideration.

Although the overall survival data is not mature, a subgroup analysis of women with a “poor prognosis” (defined as FIGO stage III patients debulked to >1.0cm of visible diease or FIGO stage IV with debulking) was performed. Within this subgroup, there were 79 deaths within the bevacizumab arm and 109 deaths in the control arm. Based on this data, there was a 36% reduction in the risk of death (HR=0.64, 95% CI=0.48 to 0.85, p=0.0022 with p=0.015 for test for interaction (treatment/risk group)) among the poor prognosis subgroup.  This result was statistically significant. “We have previously shown that [the high-risk] group has a greater benefit from bevacizumab than the other patients,” said Dr. Kristensen. “For this group, there is a very clear gain for overall survival.”

  • ICON7 Study Commentary

“We conclude that the addition of concurrent and continued bevacizumab for 12 months does improve progression-free survival,” said Dr. Kristensen.  Kristensen also noted that, on the basis of an interim analysis involving approximately 53% of the number of deaths needed for the final analysis, there is an overall trend for improvement in overall survival.

“In this study, we see the ability of antiangiogenic therapy to delay the progression of ovarian cancer, this time in the first-line setting,” said Andrew Seidman, M.D. He added that previous studies have demonstrated the efficacy of bevacizumab in ovarian cancer. “These lend support to a potential role for bevacizumab as the first biologic agent to be used in this disease,” said Seidman, who moderated a press briefing during which study highlights were presented.

There are many strengths in a study like this, in that it addresses questions about the role of anti-VEGF therapies in this setting, said Anil Sood, M.D., who served as a discussant for this paper. “The randomized design is obviously a major strength.”

However, there are potential issues to examine, explained Dr. Sood. “One is the role of bevacizumab in the combination setting, compared with the maintenance setting.”

“How useful is bevacizumab in the combination setting up front? Is the real role for bevacizumab in the maintenance setting following initial chemotherapy,” he asked.

The issue of bevacizumab dosing was also raised by Dr. Sood. “One of the questions is whether higher doses are needed,” he said. “There are data emerging from other studies showing that lower doses are as efficacious, if not more so.”

References:

1/Rudlowski C, Pickart AK, Fuhljahn C, et. al. Prognostic significance of vascular endothelial growth factor expression in ovarian cancer patients: a long-term follow-up. Int J Gynecol Cancer. 2006 Jan-Feb;16 Suppl 1:183-9. PubMed PMID: 16515588.

2/Cooper BC, Ritchie JM, Broghammer CL, et. al. Preoperative serum vascular endothelial growth factor levels: significance in ovarian cancer. Clin Cancer Res. 2002 Oct;8(10):3193-7.  PMID: 12374688

3/Aghajanian C, Finkler NJ, Rutherford T, et. alOCEANS: A randomized, double-blinded, placebo-controlled phase III trial of chemotherapy with or without bevacizumab (BEV) in patients with platinum-sensitive recurrent epithelial ovarian (EOC), primary peritoneal (PPC), or fallopian tube cancer (FTC)J Clin Oncol 29: 2011 (suppl; abstr LBA5007)[2011 American Society of Clinical Oncology Annual Meeting].

4/ Burger RA, Brady MF, Bookman MA, et. alPhase III trial of bevacizumab in the primary treatment of advanced epithelial ovarian cancer (EOC), primary peritoneal cancer (PPC), or fallopian tube cancer (FTC): a Gynecologic Oncology Group study [GOG 218 Abstract]J Clin Oncol 28:18s, 2010 (suppl; abstr LBA1).

5/Kristensen G, Perren T, Qian W., et. alResult of interim analysis of overall survival in the GCIG ICON7 phase III randomized trial of bevacizumab in women with newly diagnosed ovarian cancerJ Clin Oncol 29: 2011 (suppl; abstr LBA5006) [2011 American Society of Clinical Oncology Annual Meeting].

Additional Sources & Helpful Information:

Bevacizumab (Avastin®) Clinical Trial Information

Related WORD of HOPE Ovarian Cancer Podcast™

Related Libby’s H*O*P*E*™ Postings

Related Libby’s H*O*P*E*™ Videos

  • To view videos regarding bevacizumab (Avastin®), click here.


2010-2011 U.S. News & World Report “Best Hospitals” List

This week, U.S. News & World Report issued its 2010-2011 rankings of the best U.S. hospitals for adults. The University of Texas, M.D. Anderson Cancer Center is rated #1 in cancer treatment, and Johns Hopkins is rated #1 in gynecology and #1 overall based upon all medical specialties.

If you would like more information regarding the 2010-2011 U.S. News & World Report best U.S. hospital rankings, click here. To better understand how U.S. News & World Report ranked the hospitals in each specialty, read Best Hospitals 2010-11: The Methodology, written by U.S. News & World Report’s Avery Comarow.  If you would like to review the current U.S. News & World Report America’s Best Children’s Hospitals list, click here.

Top 10 U.S. Hospitals: Cancer

Top 10 U.S. Hospitals: Gynecology

Top 10 U.S. Hospitals (highest scores in at least six medical specialties)
1. Univ. of Texas M.D. Anderson Cancer Center, Houston, Texas Johns Hopkins Hospital, Baltimore, Maryland Johns Hopkins Hospital, Baltimore, Maryland
2. Memorial Sloan-Kettering Cancer Center, New York, New York Mayo Clinic, Rochester, Minnesota Mayo Clinic, Rochester, Minnesota
3. Mayo Clinic, Rochester, Minnesota Brigham and Women’s Hospital,Boston, Massachusetts Massachusetts General Hospital, Boston, Massachusetts
4. Johns Hopkins Hospital, Baltimore, Maryland Cleveland Clinic, Cleveland, OH Cleveland Clinic, Cleveland, Ohio
5. University of Washington Medical Center, Seattle, Washington Massachusetts General Hospital, Boston, Massachusetts Ronald Reagan UCLA Medical Center, Los Angeles
6. Dana-Farber Cancer Institute, Boston, Massachusetts Magee-Womens Hospital of Univ. of Pittsburgh Medical Center, Pittsburgh, Pennsylvania New York-Presbyterian Univ. Hospital of Columbia & Cornell, New York, New York
7. Massachusetts General Hospital, Boston, Massachusetts Duke University Medical Center, Durham, North Carolina Univ. of California, San Francisco (UCSF) Medical Center
8. Univ. of California, San Francisco (UCSF) Medical Center Univ. of California, San Francisco (UCSF) Medical Center Barnes-Jewish Hospital/Washington University, St. Louis
9. Cleveland Clinic, Cleveland, Ohio New York-Presbyterian Univ. Hospital of Columbia & Cornell, New York, New York Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
10. Ronald Reagan UCLA Medical Center, Los Angeles Memorial Sloan-Kettering Cancer Center, New York, New York Duke University Medical Center, Durham, North Carolina

MAGP2 Gene Expression Signature: A Potential Ovarian Cancer Personalized Treatment Target

A multi-institutional study has identified a potential personalized treatment target for the most common form of ovarian cancer. In the December 8 issue of Cancer Cell, the research team describes finding that a gene called MAGP2 – not previously associated with any type of cancer – was overexpressed in papillary serous ovarian tumors of patients who died more quickly. They also found evidence suggesting possible mechanisms by which MAGP2 may promote tumor growth.

A multi-institutional study has identified a potential personalized treatment target for the most common form of ovarian cancer. In the December 8 issue of Cancer Cell, the research team describes finding that a gene called MAGP2 (microfibril-associated glycoprotein 2) – not previously associated with any type of cancer – was overexpressed in papillary serous ovarian tumors of patients who died more quickly. They also found evidence suggesting possible mechanisms by which MAGP2 may promote tumor growth.

Michael Birrer, MD, Ph.D., Professor, Department of Medicine, Harvard Medical School; Director GYN/Medical Oncology, Medicine, Massachusetts General Hospital

“Ovarian cancer is typically diagnosed at an advanced stage when it is incurable, and the same treatments have been used for virtually all patients,” says Michael Birrer, MD, PhD, director of medical gynecologic oncology in the Massachusetts General Hospital (MGH) Cancer Center, and the study’s corresponding author. “Previous research from my lab indicated that different types and grades of ovarian tumors should be treated differently, and this paper now shows that even papillary serous tumors have differences that impact patient prognosis.” Birrer was with the National Institutes of Health when this study began but later joined the MGH Cancer Center.

The fifth most common malignancy among U.S. women, ovarian cancer is expected to cause approximately 15,000 deaths during 2009. Accounting for 60 percent of ovarian cancers, papillary serous tumors are typically diagnosed after spreading beyond the ovaries. The tumors typically return after initial treatment with surgery and chemotherapy, but while some patients die a few months after diagnosis, others may survive five years or longer while receiving treatment.

To search for genes expressed at different levels in ovarian cancer patients with different survival histories, which could be targets for new treatments, the researchers conducted whole-genome profiling of tissue samples that had been microdissected – reducing the presence of non-tumor cells – from 53 advanced papillary serous ovarian cancer tumors. Of 16 genes that appeared to have tumor-associated expression levels, MAGP2 had the strongest correlation with reduced patient survival.

Further analysis confirmed that MAGP2 expression was elevated in another group of malignant ovarian cancer tumors but not in normal tissue. MAGP2 gene expression was also reduced in patients whose tumors responded to chemotherapy. Recombinant expression of MAGP2 in samples of the endothelial cells that line blood vessels caused the cells to migrate and invade normal tissue.  In addition, MAGP2 gene overexpression increased microvessel density — a measurement used to determine the extent of tumor angiogenesis. The latter two observations suggest a potential role for MAGP2 gene overexpression in the growth of an ovarian cancer tumor’s blood supply.

“By confirming that different ovarian tumors have distinctive gene signatures that can predict patient prognosis, this study marks the beginning of individualized care for ovarian cancer,” says Birrer, a professor of Medicine at Harvard Medical School. “MAGP2 and the biochemical pathways it contributes to are definitely targets for new types of therapies, and we plan to pursue several strategies to interfere with tumor-associated pathways. But first we need to validate these findings in samples from patients treated in clinical trials.”

About The Study

Co-lead authors of the Cancer Cell paper are Samuel Mok, M.D., M.D. Anderson Cancer Center, and Tomas Bonome, National Cancer Institute (NCI). Additional co-authors are Kwong-Kowk Wong, M.D. Anderson; Vinod Vathipadiekal, Aaron Bell, Howard Donninger, Laurent Ozbun, Goli Samimi, John Brady, Mike Randonovich, Cindy Pise-Masison, and Carl Barrett, NCI; Michael Johnson, Dong-Choon Park, William Welch and Ross Berkowitz, Brigham and Women’s Hospital; Ke Hao and Wing Wong, Harvard School of Public Health; and Daniel Yip, University of South Florida. The study was supported by grants from the National Institutes of Health, the Ovarian Cancer Research Fund and the National Cancer Institute.

About Massachusetts General Hospital

Massachusetts General Hospital, established in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of more than $600 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, systems biology, transplantation biology and photomedicine.

Sources:

M.D. Anderson Study Predicts Dramatic Growth in Cancer Rates Among U.S. Elderly, Minorities

” … Over the next 20 years, the number of new cancer cases diagnosed annually in the United States will increase by 45 percent, from 1.6 million in 2010 to 2.3 million in 2030, with a dramatic spike in incidence predicted in the elderly and minority populations, according to research from The University of Texas M. D. Anderson Cancer Center. …Given these statistics, the role of screening and prevention strategies becomes all the more vital and should be strongly encouraged, said [Ben] Smith [M.D.]. … These findings also highlight two issues that must be addressed simultaneously: clinical trial participation and the increasing cost of cancer care. Historically, both older adults and minorities have been under-represented in such studies, and, therefore, vulnerable to sub-optimal cancer treatment. Simultaneously, over the past decade in particular, the cost of cancer care is growing at a rate that’s not sustainable. …”

“Research underscores impact on health care system, importance of screenings, prevention strategies, inclusive clinical trials

Cancer Newsline Podcast
M. D. Anderson audio player (click & play)
Dramatic Growth in Cancer Rates Among Elderly, Minorities

Over the next 20 years, the number of new cancer cases diagnosed annually in the United States will increase by 45 percent, from 1.6 million in 2010 to 2.3 million in 2030, with a dramatic spike in incidence predicted in the elderly and minority populations, according to research from The University of Texas M. D. Anderson Cancer Center.

The study, published online today in Journal of Clinical Oncology, is the first to determine such specific long-term cancer incidence projections. It predicts a 67 percent increase in the number of adults age-65-or-older diagnosed with cancer, from 1 million in 2010 to 1.6 million in 2030. In non-white individuals over the same 20-year span, the incidence is expected to increase by 100 percent, from 330,000 to 660,000.

Ben Smith, M.D., Adjunct Assistant Professor, Department of Radiation Oncology, The University of Texas M.D. Anderson Center

Ben Smith, M.D., Adjunct Assistant Professor, Department of Radiation Oncology, The University of Texas M.D. Anderson Cancer Center

According to Ben Smith, M.D., adjunct assistant professor in M. D. Anderson’s Department of Radiation Oncology, the study underscores cancer’s growing stress on the U.S. health care system.

‘In 2030, 70 percent of all cancers will be diagnosed in the elderly and 28 percent in minorities, and the number of older adults diagnosed with cancer will be the same as the total number of Americans diagnosed with cancer in 2010,’ said Smith, the study’s senior author. ‘Also alarming is that a number of the types of cancers that are expected to increase, such as liver, stomach and pancreas, still have tremendously high mortality rates.’

Unless specific prevention and/or treatment strategies are discovered, cancer death rates also will increase dramatically, said Smith, who is currently on active military duty and is stationed at Lackland Air Force Base.

To conduct their research, Smith and his team accessed the United States Census Bureau statistics, updated in 2008 to project population growth through 2050, and the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) registry, the premier population-based cancer registry representing 26 percent of the country’s population. Cancer incidence rates were calculated by multiplying the age, sex, race and origin-specific population projections by the age, sex, race and origin-specific cancer incidence rates.

The researchers found that from 2010 to 2030, the population is expected to grow by 19 percent (from 305 to 365 million). The total number of cancer cases will increase by 45 percent (from 1.6 to 2.3 million), with a 67 percent increase in cancer incidence in older Americans (1 to 1.6 million), compared to an 11 percent increase in those under the age of 65 (.63 to .67 million).

With respect to race, a 100 percent increase in cancer is expected for minorities (.33 to .66 million); in contrast, in white Americans, a 31 percent increase is anticipated (1.3 to 1.7 million). The rates of cancer in blacks, American Indian-Alaska Native, multi-racial, Asian-Pacific Islanders and Hispanics will increase by 64 percent, 76 percent, 101 percent, 132 percent and 142 percent, respectively.

Regarding disease-specific findings, Smith and his team found that the leading cancer sites are expected to remain constant – breast, prostate, colon and lung. However, cancer sites with the greatest increase in incidence expected are: stomach (67 percent); liver (59 percent); myeloma (57 percent); pancreas (55 percent); and bladder (54 percent).

Given these statistics, the role of screening and prevention strategies becomes all the more vital and should be strongly encouraged, said Smith. In the study, Smith and his team site [sic]: vaccinations for hepatitis B and HPV; the chemoprevention agents tamoxifen and raloxifene; interventions for tobacco and alcohol; and removal of pre-malignant lesions, such as colon polyps.

These findings also highlight two issues that must be addressed simultaneously: clinical trial participation and the increasing cost of cancer care. Historically, both older adults and minorities have been under-represented in such studies, and, therefore, vulnerable to sub-optimal cancer treatment. Simultaneously, over the past decade in particular, the cost of cancer care is growing at a rate that’s not sustainable.

‘The fact that these two groups have been under-represented in clinical research participation, yet their incidence of cancer is growing so rapidly, reflects the need for therapeutic trials to be more inclusive and address issues that are particularly relevant to both populations,’ said Smith. ‘In addition, as we design clinical trials, we need to seek not only the treatment that will prolong survival, but prolong survival at a reasonable cost to patients. These are two issues that oncologists need to be much more concerned about and attuned to.’

Another issue that needs to be addressed is the shortage of health care professionals predicted. For example, according to a workforce assessment by American Society for Clinical Oncology (ASCO), the shortage of medical oncologists will impact the health care system by 2020. Smith said ASCO and other professional medical organizations beyond oncology are aware of the problem, and are actively engaged in efforts to try and grow the number of physicians, as well as encourage the careers of nurse practitioners and physician assistants who are part of the continuum of care, to best accommodate the increase in demand forecasted.

‘There’s no doubt the increasing incidence of cancer is a very important societal issue. There will not be one solution to this problem, but many different issues that need to be addressed to prepare for these changes,’ said Smith. ‘I’m afraid if we don’t come to grips with this as a society, health care may be the next bubble to burst.’

In addition to Smith, other M. D. Anderson authors on the study include: Thomas Buchholz, M.D., professor and chair of the Department of Radiation Oncology and the study’s senior author; Gabriel Hortobagyi, M.D., professor and chair of the Department of Breast Medical Oncology; and Grace Smith, M.D., Ph.D., assistant professor in the Department of Radiation Oncology. Arti Hurria, M.D., post-doctoral fellow in the Department of Medical Oncology, City of Hope Cancer Center, also is a contributing author on the study.”

Sources:

Genetic Variations In miRNA Processing Pathway & Binding Sites Help Predict Ovarian Cancer Risk

“Genetic variations in the micro-RNA (miRNA) processing pathway genes and miRNA binding sites predict a woman’s risk for developing ovarian cancer and her prospects for survival, researchers from The University of Texas M. D. Anderson Cancer Center reported at the 100th annual meeting of the American Association for Cancer Research. … The unique study was the first to examine the association of genetic variants related to miRNA with ovarian cancer risk, overall survival for ovarian cancer patients, and platinum-based chemotherapy response. …”

Genetic variations in miRNA processing pathway and binding sites help predict ovarian cancer risk – Several variations indicate likelihood of response to platinum-based chemotherapy

DENVER – Genetic variations in the micro-RNA (miRNA) processing pathway genes and miRNA binding sites predict a woman’s risk for developing ovarian cancer and her prospects for survival, researchers from The University of Texas M. D. Anderson Cancer Center reported at the 100th annual meeting of the American Association for Cancer Research.

wu

Xifeng Wu, M.D., Ph.D., Professor, Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center

‘We found a gene dosage effect, the more unfavorable variations a woman has, the greater her ovarian cancer risk and the shorter her survival time,’ said senior author Xifeng Wu, M.D., Ph.D., professor in M. D. Anderson’s Department of Epidemiology. Median survival, for example, ranged from 151 months for women with fewest unfavorable variations to 24 months for those with the most.

Several variations also indicate likely response to platinum-based chemotherapy.

‘Our findings have the potential clinical application of indicating a patient’s prognosis and showing who will respond to different therapies by analyzing a single blood sample,’ Wu said. ‘We also will incorporate this genetic information with epidemiological information to build a comprehensive model to predict susceptibility to ovarian cancer.’

The team chose the miRNA processing pathway because it is crucial to production of miRNAs, the small molecules that regulate between one third and half of all genes. The researchers also chose the binding sites on host genes where miRNAs exert their effects on gene expression.

They analyzed 219 potential functional single nucleotide polymorphisms (SNPs) – variations of a single DNA building block in a gene – in eight genes that process miRNA and at the miRNA binding sites of 129 cancer-relevant genes. The study examined genetic information from 417 cancer patients and 417 healthy controls. To minimize the possible confounding effects of ethnicity, 339 Caucasian cases and 349 controls were analyzed.

They discovered 12 SNPs to be significantly associated with ovarian cancer risk. Moreover, compared to women with five or fewer unfavorable genotypes, women with eight or more of these unfavorable genotypes were 4.5 times more likely to develop ovarian cancer and women with six to eight unfavorable SNPs were at twice the risk.

The team also found 21 SNPs significantly associated with overall survival. Median survival was 151 months for women with six or fewer unfavorable variations; 42 months for those with seven to nine unfavorable variations; and 24 months for those with 10 or more. One of the outcome risk SNPs also was strongly associated with platinum-based chemotherapy response, with those having the SNP 3.4 times less likely to respond to chemotherapy.

Wu collaborated with Dong Liang, Ph.D, in the College of Pharmacy and Health Sciences, Texas Southern University, and Karen Lu, M.D., professor in M. D. Anderson’s Department of Gynecologic Oncology, on this study.

The unique study was the first to examine the association of genetic variants related to miRNA with ovarian cancer risk, overall survival for ovarian cancer patients, and platinum-based chemotherapy response. Such a wide-ranging inquiry was made possible by M. D. Anderson’s extensive clinical and genetic data sets, Wu said.

Co-authors with Wu, first author Liang, Ph.D., and Lu are; Jie Lin, Ph.D., Xia Pu, Yuanqing Ye, Ph.D., all in the Department of Epidemiology; and Larissa Meyer, M.D., in the Department of Gynecologic Oncology at M. D. Anderson Cancer Center. Pu is a graduate student at The University of Texas Graduate School of Biomedical Sciences at Houston, which is a joint effort of M. D. Anderson and The University of Texas Health Science Center at Houston.

This research was supported by an award by the Department of Defense Ovarian Cancer Research Program.”

About M. D. Anderson

The University of Texas M. D. Anderson Cancer Center in Houston ranks as one of the world’s most respected centers focused on cancer patient care, research, education and prevention. M. D. Anderson is one of only 40 comprehensive cancer centers designated by the National Cancer Institute. For four of the past six years, including 2008, M. D. Anderson has ranked No. 1 in cancer care in “America’s Best Hospitals,” a survey published annually in U.S. News & World Report.

Sources:

Tumor-Promoting Protein COX-2 Is The Target Of First Joint Symposium Between AACR & ASCO

An inflammatory protein implicated in a variety of cancers is the target of the first joint symposium between the nation’s two premier cancer research organizations.  The presidents of the American Association for Cancer Research (AACR) and the American Society of Clinical Oncology (ASCO) organized the session focused on the COX-2 enzyme and cancer treatment Monday afternoon — April 20, 2:30-4:30 p.m., in rooms 205-207 of the Colorado Convention Center — at the AACR’s 100th Annual Meeting 2009 in Denver.  A similar symposium on new molecular targets will be conducted at ASCO’s annual meeting in May 29- June 2 in Orlando.  COX-2 is best known as a target for preventing dangerous polyps that lead to colorectal cancer, but it is also advancing as a target for treatment of many solid tumors. …

“Leading cancer organizations team up on tumor-promoting protein – AACR and ASCO begin joint symposia at annual meetings with focus on COX-2

An inflammatory protein implicated in a variety of cancers is the target of the first joint symposium between the nation’s two premier cancer research organizations.

duboismdander

Raymond DuBois, M.D., Ph.D., President, AACR; Provost and Executive Vice President, The University of Texas M. D. Anderson Cancer Center

The presidents of the American Association for Cancer Research (AACR) and the American Society of Clinical Oncology (ASCO) organized the session focused on the COX-2 enzyme and cancer treatment Monday afternoon — April 20, 2:30-4:30 p.m., in rooms 205-207 of the Colorado Convention Center — at the AACR’s 100th Annual Meeting 2009 in Denver. A similar symposium on new molecular targets will be conducted at ASCO’s annual meeting in May 29- June 2 in Orlando.

COX-2 is best known as a target for preventing dangerous polyps that lead to colorectal cancer, but it is also advancing as a target for treatment of many solid tumors.

‘Our symposium is timely because we are starting to see data from Phase II and Phase III clinical trials about COX-2 inhibition following post-surgical chemotherapy in colon cancer patients,’ said Raymond DuBois, M.D., Ph.D., president of AACR and provost and executive vice president at The University of Texas M. D. Anderson Cancer Center.

‘There’s been a great deal of preclinical and translational research addressing COX-2 overexpression in tumors and its role in cancer growth and survival. In prevention, inhibiting this enzyme reduces the number of high-risk precancerous polyps by 66 percent,’ DuBois said. ‘The time is ripe to combine basic science and clinical expertise to advance the therapeutic potential of this approach.’

Joint efforts are critical to the development of new approaches against cancer, said ASCO President Richard L. Schilsky, M.D., professor of medicine at the University of Chicago Medical Center.

‘The development of targeted therapies for cancer prevention and treatment requires the close collaboration and combined resources of basic scientists and clinical investigators,’ Schilsky said. ‘The success of targeted therapy for cancer depends first and foremost on a comprehensive understanding of the biology of the drug target coupled with a robust assay to assess target inhibition and a drug that hits the target. With these ingredients in place, clinical trials can be designed to assess the impact of treatment in the population most likely to benefit.’

schilsky

Richard L. Schilsky, M.D., President, ASCO; Associate Dean for Clinical Research, Professor of Medicine at the University of Chicago Medical Center.

‘The AACR/ASCO Symposium illustrates these core principles and demonstrates that continued progress against cancer requires the partnership of all investigators and practitioners represented by these two great organizations,’ Schilsky said.

The idea for joint symposia at each organization’s annual meeting has been discussed for years and was advanced by immediate past presidents William Hait, M.D., Ph.D., of AACR and Nancy Davidson, M.D., of ASCO.

DuBois and Schilsky co-chair the symposium. Scheduled presentations are:

  • COX-2 and Cancer Biology by DuBois, who discovered the enzyme’s overexpression in tumors.
  • Overview of COX-2 as a Target for Cancer Treatment, by Schilsky.

*          *          *

AACR is the world’s oldest and largest professional organization dedicated to advancing cancer research. ASCO is the world’s leading professional organization representing physicians who care for people with cancer. Many scientists and physicians are members of both organizations.”

Source: Leading Cancer Organizations Team Up on Tumor-Promoting Protein – AACR and ASCO begin joint symposia at annual meetings with focus on COX-2, M.D. Anderson News Release, The University of Texas M.D. Anderson Cancer Center, April 17, 2009.

Comment:  The relationship between ovarian cancer and COX-2 remains unclear.  Some in vitro and in vivo studies make a connection between ovarian cancer and COX-2, while others suggest that COX-1 is more relevant to current ovarian cancer research.  It is an area that warrants further investigation.

Recent Studies Re Ovarian Cancer and COX-2:

Routine Screening for Hereditary Breast and Ovarian Cancer Recommended By ACOG & SGO

Evaluating a patient’s risk of hereditary breast and ovarian cancer syndrome is an important first step in cancer prevention and early detection and should be a routine part of ob-gyn practice. Those who are likely to have the syndrome should be referred for further assessment to a clinician with expertise in genetics, according to a new Practice Bulletin jointly released today by The American College of Obstetricians and Gynecologists [ACOG] and the Society of Gynecologic Oncologists [SGO]. The new document also provides information on how to counsel patients with hereditary risk in cancer prevention and how to perform surgical removal of the ovaries and fallopian tubes in this population

“Routine Screening for Hereditary Breast and Ovarian Cancer Recommended

Washington, DC — Evaluating a patient’s risk of hereditary breast and ovarian cancer syndrome is an important first step in cancer prevention and early detection and should be a routine part of ob-gyn practice. Those who are likely to have the syndrome should be referred for further assessment to a clinician with expertise in genetics, according to a new Practice Bulletin jointly released today by The American College of Obstetricians and Gynecologists [ACOG] and the Society of Gynecologic Oncologists [SGO]. The new document also provides information on how to counsel patients with hereditary risk in cancer prevention and how to perform surgical removal of the ovaries and fallopian tubes in this population.

Hereditary breast and ovarian cancer syndrome is an inherited cancer-susceptibility syndrome marked by multiple family members with breast cancer, ovarian cancer or both; the presence of both breast and ovarian cancer in a single individual; and early age of breast cancer onset.

lu-karen-pic

Karen Lu, M.D., Professor of Gynecologic Oncology at the University of Texas MD Anderson Cancer Center

‘The vast majority of families who have hereditary breast and ovarian cancer syndrome carry an inherited mutation of the BRCA1 or BRCA2 tumor suppressor genes. Women in these families may have a higher risk of breast, ovarian, peritoneal, and fallopian tube cancers,’ said Karen Lu, MD, professor of gynecologic oncology at the University of Texas MD Anderson Cancer Center, who helped develop the ACOG Practice Bulletin. ‘Though having a BRCA gene mutation does not mean an individual will undoubtedly develop cancer, it is better to know sooner rather than later who may be at risk.’

Women with either BRCA mutation have a 65%-74% chance of developing breast cancer in their lifetime. Ovarian cancer risk is increased by 39%-46% in women with a BRCA1 mutation and by 12-20% in women with a BRCA2 mutation. Approximately 1 in 300 to 1 in 800 individuals in the US are BRCA carriers. BRCA mutations may occur more frequently in some populations founded by small ancestral groups, such as Ashkenazi (Eastern European) Jews, French Canadians, and Icelanders. An estimated 1 in 40 Ashkenazi Jews has a BRCA1 or BRCA2 mutation.

The new document addresses the ob-gyn’s role in identifying, managing, and counseling patients with an inherited cancer risk. The initial screening evaluation should include specific questions about personal and family history of breast cancer and ovarian cancer. Because BRCA mutations can be passed down from both the father’s and mother’s side of the family, both sides of a woman’s family should be carefully examined. Obtaining a full family history may be impeded in women who were adopted, those from families that have multiple women who had a hysterectomy and oophorectomy at a young age, or those from families with few female relatives. The results of a general evaluation will help determine whether the patient would benefit from a more in-depth hereditary cancer risk assessment, which should be conducted by a health care provider with expertise in cancer genetics.

Further genetic risk assessment is recommended for women who have more than a 20%-25% chance of having an inherited predisposition to breast or ovarian cancer. These women include:

  • Women with a personal history of both breast cancer and ovarian cancer
  • Women with ovarian cancer and a close relative—defined as mother, sister, daughter, grandmother, granddaughter, aunt—with ovarian cancer, premenopausal breast cancer, or both
  • Women of Ashkenazi Jewish decent with breast cancer who were diagnosed at age 40 or younger or who have ovarian cancer
  • Women with breast cancer at 50 or younger and who have a close relative with ovarian cancer or male breast cancer at any age
  • Women with a close relative with a known BRCA mutation

Genetic risk assessment may also be appropriate for women with a 5%-10% chance of having hereditary risk, including:

  • Women with breast cancer by age 40
  • Women with ovarian cancer, primary peritoneal cancer, or fallopian tube cancer or high grade, serous histology at any age
  • Women with cancer in both breasts (particularly if the first cancer was diagnosed by age 50)
  • Women with breast cancer by age 50 and a close relative with breast cancer by age 50
  • Women with breast cancer at any age and two or more close relatives with breast cancer at any age (particularly if at least one case of breast cancer was diagnosed by age 50)
  • Unaffected women with a close relative that meets one of the previous criteria

Before testing, a genetic counselor can discuss the possible outcomes of testing; options for surveillance, chemoprevention, and risk-reducing surgery; cost and legal and insurance matters surrounding genetic tests and test results; and the psychologic and familial implications that may follow. The counselor can also provide written materials that women can share with family members who may also have an inherited risk.

Screening, Prevention, and Surgical Intervention

Those with hereditary breast and ovarian cancer syndrome can begin a screening and prevention plan based on individual risk factors and family history. Ovarian cancer screening approaches are currently limited. For women with a BRCA mutation, ACOG recommends periodic screening with CA 125 and transvaginal ultrasonography beginning between the ages of 30 and 35 years or 5-10 years earlier than the earliest age of first diagnosis of ovarian cancer in the family.

Risk-reducing salpingo-oophorectomy surgery—which removes both of the ovaries and fallopian tubes—can reduce the risk of ovarian and fallopian tube cancer by about 85% to 90% among BRCA carriers. Women who have BRCA1 or BRCA2 mutations should be offered risk-reducing salpingo-oophorectomy by age 40 or when childbearing is complete. The ideal time for this surgery depends on the type of gene mutation.

‘In this population, risk-reducing salpingo-oophorectomy and pathology review must be extremely comprehensive to check for microscopic cancers in the ovaries, fallopian tubes, and abdominal cavity,’ Dr. Lu said. According to the Practice Bulletin, all tissue from the ovaries and fallopian tubes should be removed, and a complete, serial sectioning that includes microscopic examination for occult cancer should be conducted. A thorough visualization of the peritoneal surfaces with pelvic washings should be performed. Any abnormal areas should undergo biopsy.

Strategies recommended to reduce breast cancer risk in women with a BRCA mutation include semiannual clinical breast examination; an annual mammogram and annual breast magnetic resonance imaging screening beginning at age 25 or sooner based on the earliest age onset in the family; chemoprevention therapy with tamoxifen; and bilateral mastectomy to remove both breasts, which reduces the risk of breast cancer by greater than 90%-95%.

Practice Bulletin #103 “Hereditary Breast and Ovarian Cancer Syndrome” is published in the April 2009 edition of Obstetrics & Gynecology.”

_______________________________________________________

About the American College of Obstetricians & Gynecologists

The American College of Obstetricians and Gynecologists is the national medical organization representing over 53,000 members who provide health care for women.

About the Society of Gynecologic Oncologists

The Society of Gynecologic Oncologists is a national medical specialty organization of physician-surgeons who are trained in the comprehensive management of women with malignancies of the reproductive tract.  The purpose of the SGO is to improve the care of women with gynecologic cancers by encouraging research and disseminating knowledge to raise the standards of practice in the prevention and treatment of gynecologic malignancies, in cooperation with other organizations interested in women’s health care, oncology and related fields. This is reflected in the Society’s Mission statement to “promote and ensure the highest quality
of comprehensive clinical care through excellence in education and research in gynecologic cancers.”

Primary Source:  Routine Screening for Hereditary Breast and Ovarian Cancer Recommended, News Release, American College of Obstetricians & Gynecologists, March 20, 2009.

MK-0457 Alone and in Combination With Docetaxel Inhibits Ovarian Cancer Growth In Vivo

…[T]he [M.D. Anderson Cancer Center & Baylor College of Medicine] researchers concluded that [Aurora kinase] AK inhibition [produced by MK-0457] significantly reduces ovarian cancer tumor burden and cell proliferation, and increases tumor cell apoptosis in preclinical ovarian cancer mouse models. The researchers noted that the role of Aurora kinase inhibition in ovarian cancer merits further investigation in clinical trials.

Chemotherapeutic drugs that interfere with the normal progression of cell division are used regularly for anti-cancer treatment. These so-called “antimitotic” drugs work by halting the cell cycle in mitosis, thereby inducing cell death (apoptosis) in tumor cells. Unfortunately, these compounds act not only on proliferating tumor cells, but exhibit significant side effects on non-proliferating or normal cells.

Aurora kinases (AKs), a specific family of protein kinases, are essential for various steps in human cell division. The cell division process is one of the hallmarks of every living organism. Within the complete cell-cycle process, mitosis constitutes one of the most critical steps. The main purpose of mitosis is to segregate sister chromatids into two daughter cells. This process is tightly regulated by several proteins, some of them acting as check points that ultimately ensure the correct coordination of this critical biologic process.

There is evidence linking AK overexpression with various types of malignant human cancer cells. Given the potential selectivity to target tumor cells while leaving normal cells unaffected, several “AK inhibitors” have been developed by various drug companies. Researchers at the University of Texas M.D. Anderson Cancer Center (Departments of Gynecologic Oncology, Surgical Oncology, and Cancer Biology) and the Baylor College of Medicine (Departments of Molecular and Cellular Biology and Obstetrics and Gynecology) tested MK-0457, a small molecule AK inhibitor, alone and in combination with docetaxel against ovarian cancer growth in vitro and in vivo. MK0457, initially developed by Vertex Pharmaceuticals Inc. (Vertex), is now being developed clinically by Merck & Co., Inc (Merck) for use against treatment-resistant forms of advanced leukemias.

The in vitro testing conducted by M.D. Anderson and Baylor researchers compared the use of docetaxel alone with the combination use of docetaxel and MK-0457, against two lines of chemosensitive ovarian cancer cells. Notably, the M.D. Anderson and Baylor researchers determined that the docetaxel and MK-0457 combination produced cytotoxicity that was 10 times greater than that produced by docetaxel alone. The in vivo testing, conducted in mouse models, compared the use of MK-0457 monotherapy against lines of chemosensitive and chemoresistant ovarian cancer cells. The AK inhibitor MK-0457, when used alone, significantly reduced ovarian cancer cell tumor burden. Combination treatment with docetaxel and MK-0457 resulted in significantly improved reduction in tumor growth, as well as a threefold increase in cell death, as compared to docetaxel monotherapy.

Based upon the foregoing results, the researchers concluded that AK inhibition significantly reduces ovarian cancer tumor burden and cell proliferation, and increases tumor cell apoptosis in preclinical ovarian cancer mouse models. The researchers noted that the role of Aurora kinase inhibition in ovarian cancer merits further investigation in clinical trials.

Note: In November 2007, Merck suspended new patient enrollment in two leukemia trials which involve the use of MK-0457. The suspension of new enrollees was attributable to preliminary safety data that indicated a potential cardiovascular effect in one patient. The safety findings from that patient indicated “QTc prolongation” (or “Long QT Syndrome“), a condition that can precede sudden cardiac arrest. Patients already enrolled in the two leukemia trials were permitted to continue treatment with MK-0457, provided that they were monitored for QTc prolongation. To our knowledge, based upon publicly available information, there have been no further reports of QTc prolongation within those two clinical trials.

Primary Reference: Targeting Aurora Kinase with MK-0457 Inhibits Ovarian Cancer Growth; Lin, YG et. al., Clin Cancer Res. 2008 Sep 1;14(17):5437-5446

Secondary References:

Working Smarter, Not Harder: Use of Anti-Estrogen Therapy to Battle Recurrent Ovarian Cancer

The Gynecologic Oncology department of the University of Texas, M.D. Anderson Cancer Center took a page out of the breast cancer treatment “playbook,” and conducted a single institution Phase II clinical trial using letrozole (Femara®) to treat recurrent, platinum and taxane resistant, high-grade cancer of the ovary and peritoneum. …The trial investigators concluded that 26% (8/31 pts.) of patients with ER+ … ovarian and primary peritoneal cancer derived a clinical benefit (stable disease (SD) + partial response (PR)) after treatment with letrozole (Femara®).

Pursuant to the breast cancer standard of care, breast tissue tumor is routinely analyzed to determine if it is “estrogen receptor positive” (ER positive or ER+), meaning that tumor growth is fueled by the hormone estrogen. It is well-known in the breast cancer area that hormonal therapy is a very effective treatment against breast cancer that is ER+. Sometimes referred to as “anti-estrogen therapy,” hormonal therapy blocks the ability of the hormone estrogen to turn on and stimulate the growth of breast cancer cells.

For decades, the anti-estrogen therapy of choice for treatment of ER+ breast cancer was tamoxifen. In 2005, several world-wide clinical trials reported that aromatase inhibitors (specifically, anastrozole (Arimidex®), exemestane (Aromasin®), and letrozole (Femara®) were more effective than tamoxifen in post-menopausal women with ER+ breast cancer. Aromatase inhibitor drug use is currently the standard of care for treatment of post-menopausal women with ER+ breast cancer, while tamoxifen remains the hormonal treatment of choice for pre-menopausal women.

The Gynecologic Oncology department of the University of Texas, M.D. Anderson Cancer Center took a page out of the breast cancer treatment “playbook,” and conducted a single institution Phase II clinical trial using letrozole (Femara®) to treat recurrent, platinum and taxane resistant, high-grade cancer of the ovary and peritoneum.

Thirty-three patients enrolled in the Phase II clinical trial, and each had measurable disease that tested ER+ pursuant to trial eligibility criteria. Twenty-three patients (74%) had received three or more prior chemotherapy regimens. Letrozole (Femara®) was administered at a dose of 2.5 mg orally once daily until disease progression or toxicity occurred. The median patient age was 63 years (ranging from 38 to 83 years).

The 31 patients evaluable for response received a total of 81 cycles (4 weeks per cycle) of therapy (ranging from 1 to 14 cycles per patient). The median treatment duration was 8 weeks (ranging from 4 to 52 weeks). The trial investigators reported that (i) none of the patients had a complete response (CR), (ii) 1 (3%) had a partial response (PR), and (iii) 7 (23%) had stable disease (SD). The median duration of clinical benefit (SD and PR) was 9 weeks (ranging from 7 to 46 weeks). The median follow-up for all patients was 25 weeks. All evaluable patients were monitored for toxicity. The most common adverse effects were fatigue (36%) and diaphoresis (21%). No grade 3 or 4 toxicities were reported, and no patients discontinued treatment owing to adverse effects. Eighteen patients (58%) went on to receive additional therapy with other agents.

Based upon the results above, the trial investigators concluded that 26% (8/31 pts.) of patients with ER+, platinum- and taxane-resistant, high-grade ovarian and primary peritoneal cancer derived a clinical benefit (stable disease (SD) + partial response (PR)) after treatment with letrozole (Femara®).

Sources:

Comment: Based upon the references listed above and below, it appears that the opening of clinical trials that utilize anti-estrogen therapy to treat ER+ ovarian cancer is long overdue. The “take away” from the M.D. Anderson clinical trial study results is that an ovarian cancer survivor should request her doctor to test the ovarian cancer tumor tissue obtained from surgery or biopsy for estrogen receptor positivity, so as to determine if she is eligible to use anti-estrogen therapy (within the context of a clinical trial) as part of an overall cancer treatment plan.

It is important to note that letrozole is a low side effect, oral drug. Moreover, M.D. Anderson’s letrozole monotherapy produced a 26% clinical benefit rate among ER+, platinum- and taxane-resistant, ovarian and peritoneal cancer patients, despite the fact that approximately three-quarters of the clinical trial patients were heavily pretreated with multiple lines of chemotherapy prior to their trial enrollment. It is promising to consider the potential clinical benefit that could be generated by anti-estrogen therapy in a neoadjuvant or adjuvant ovarian cancer treatment setting.

Additional Anti-Estrogen Therapy/Ovarian Cancer References:

  • Estrogen-regulated gene expression predicts response to endocrine therapy in patients with ovarian cancer, Walker G et. al.; Gynecol Oncol. 2007 Sep;106(3):461-8. Epub 2007 Jul 10. (“OBJECTIVE: To explore the predictive value of estrogen-regulated gene changes as indicators of sensitivity in ovarian cancer patients treated with the aromatase inhibitor Letrozole. … CONCLUSION: These results suggest that expression levels of certain proteins in ovarian cancers are estrogen-regulated and could help identify patients who would benefit from endocrine therapy.” [i.e., anti-estrogen therapy])
  • Antiestrogen therapy is active in selected ovarian cancer cases: the use of letrozole in estrogen receptor-positive patients, Smyth JF et. al.; Clin Cancer Res. 2007 Jun 15;13(12):3617-22 (“PURPOSE: To evaluate the efficacy of the aromatase inhibitor letrozole in preselected estrogen receptor (ER)-positive relapsed epithelial ovarian cancer patients and to identify markers that predict endocrine-sensitive disease. EXPERIMENTAL DESIGN: This was a phase II study of letrozole 2.5 mg daily until clinical or marker evidence of disease progression in previously treated ER-positive ovarian cancer patients with a rising CA125 that had progressed according to Rustin’s criteria. The primary end point was response according to CA125 and response evaluation criteria in solid tumors (RECIST) criteria. Marker expression was measured by semiquantitative immunohistochemistry in sections from the primary tumor. RESULTS: Of 42 patients evaluable for CA125 response, 7 (17%) had a response (decrease of >50%), and 11 (26%) patients had not progressed (doubling of CA125) following 6 months on treatment. The median time taken to achieve the CA125 nadir was 13 weeks (range 10-36). Of 33 patients evaluable for radiological response, 3 (9%) had a partial remission, and 14 (42%) had stable disease at 12 weeks. Eleven patients (26%) had a PFS of >6 months. Subgroup analysis according to ER revealed CA125 response rates of 0% (immunoscore, 150-199), 12% (200-249), and 33% (250-300); P = 0.028, chi(2) for trend. Expression levels of HER2, insulin-like growth factor binding protein 5, trefoil factor 1, and vimentin were associated with CA125 changes on treatment. CONCLUSIONS: This is the first study of a hormonal agent in a preselected group of ER-positive ovarian cancer patients. A signature of predictive markers, including low HER2 expression, predicts response.)
  • The efficacy of tamoxifen in patients with advanced epithelial ovarian cancer, Karagol H et. al.; Med Oncol. 2007;24(1):39-43 (“BACKGROUND: Activity of tamoxifen as a salvage therapy in patients with advanced epithelial ovarian cancer was evaluated by a number of studies. In this study, we evaluated efficacy of tamoxifen in our patients with platinum-resistant epithelial ovarian carcinoma. … RESULTS: Twenty-nine eligible patients were included to the study. There were 1 (3%) complete response, 2 (7%) partial response, 6 (21%) stable disease, and 20 (69%) progressive disease. All patients were progressed after initiation of tamoxifen. Median progression-free survival was 4 mo (95% CI: 2.98-5.02). Disease progression of 19 (65%) patients were shown within the first 6 mo after initiation of tamoxifen. Progression-free survival was between 6 and 12 mo for 7 (24%) patients and > or =12 mo for 3 (10%) patients. The median survival after initiation of tamoxifen was 15 mo (95% CI: 7.2-22.8). No toxicity attributable to tamoxifen was seen in any of the patients. The only independent prognostic factor that had a significant predictive value for progression- free survival was the response to tamoxifen treatment (p = 0.043, hazard ratio: 0.12, 95% CI: 0.01-0.94). CONCLUSION: Considering minimal side effects and ability to cause objective responses, there is a place for tamoxifen in treatment of patients with platinum-resistant ovarian cancer. A phase III trial is required to confirm the value of the drug in patients presenting these clinical settings.”)
  • Anastrozole therapy in recurrent ovarian adult granulosa cell tumors: a report of 2 cases, Freeman SA, Modesitt SC; Gynecol Oncol. 2006 Nov;103(2):755-8. Epub 2006 Jul 25 (“BACKGROUND: Ovarian sex cord stromal tumors are frequently hormonally active, and adult granulosa cell tumors often demonstrate estrogen receptor positivity. Thus, hormonal agents have been evaluated as potential treatments for advanced stage or recurrent adult granulosa cell tumors. CASE: Two cases of patients with recurrent adult granulosa cell tumors are presented. Each patient received multiple treatment modalities including chemotherapy and had previously progressed on leuprolide. Both patients were started on anastrozole with subsequent normalization of inhibin B levels and clinical exams. They have been maintained on treatment for 14 and 18 months, respectively, and have tolerated the drug without difficulty. CONCLUSION: Aromatase inhibitors may be a viable treatment option for women with advanced stage or recurrent ovarian adult granulosa cell tumors.”)
  • Hormonal therapy in epithelial ovarian cancer, Rao GG, Miller DS; Expert Rev Anticancer Ther. 2006 Jan;6(1):43-7. (“The ovary is an endocrine and end organ. Hormones and their receptors have been associated with ovarian cancer and may be related to its causation. Some data suggest that hormonal therapies may have an effect on ovarian cancer in palliative settings. The most well studied anticancer drugs are tamoxifen, megestrol acetate, medroxyprogesterone acetate, leuprolide acetate, anastrozole and letrozole. Presently, no hormonal therapy is approved by the US FDA for the treatment of any type of ovarian malignancy or is listed as an active agent by any of the authoritative compendia. Owing to the endocrine associations with ovarian cancer, the minimal side effects of hormonal therapy and the demonstrated activity of hormonal therapies in other endocrine organ-associated malignancies, further study of hormonal therapies for ovarian cancer is warranted.”)
  • Aromatase expression in ovarian epithelial cancers, Cunat S et. al.; J Steroid Biochem Mol Biol. 2005 Jan;93(1):15-24 (” … Aromatase activity was evaluated in ovarian epithelial cancer (OEC) cell lines by the tritiated water assay and the effects of third-generation aromatase inhibitors (AIs) on aromatase activity and growth were studied. Letrozole and exemestane were able to completely inhibit aromatase activity in BG1 and PEO14 cell lines. Interestingly, both AI showed an antiproliferative effect on the estrogen responsive BG1 cell line co-expressing aromatase and ERalpha. Aromatase expression was found in ovarian epithelial normal tissues and in some ovarian epithelial cancer cells and tissues. This finding raises the possibility that some tumors may respond to estrogen and provides a basis for ascertaining an antimitogenic effect of AI in a subgroup of ovarian epithelial cancers.”)
  • Hormone therapy in epithelial ovarian cancer, Makar AP; Endocr Relat Cancer. 2000 Jun;7(2):85-93 (“Although epidemiologic studies, animal experiments and receptor studies have shown that not only normal ovaries but also many malignant ovarian tumors can be considered as endocrine related and hormone dependent, the place of hormonal therapy in the management of patients with ovarian cancer remains unsettled. Most trials of hormonal treatment in ovarian cancer have been retrospective, involved only limited numbers of patients, and lacked important patient-related data and information pertaining to tumor characteristics. In addition, a variety of hormonal preparations with different degrees of potency and in different dosages were included in these studies. A literature review shows that response to hormonal therapy even in a preterminal setting, is modest, with about 8% objective response but almost no side effects. In a similar patient setting, more toxic therapeutic agents do not yield a better response. The place of hormonal therapy in the management of patients with epithelial ovarian cancer needs more thorough evaluation in well-designed randomized trials.”)

Non-Platinum Topotecan Drug Combination Therapy Provides No Survival Advantage Over Topotecan Monotherapy

“In women with recurrent ovarian cancer, treatment with topotecan along with etoposide or gemcitabine offers no survival advantage over topotecan monotherapy, German and Austrian researchers report in the July 1st issue of the Journal of Clinical Oncology.”

“In women with recurrent ovarian cancer, treatment with topotecan along with etoposide or gemcitabine offers no survival advantage over topotecan monotherapy, German and Austrian researchers report in the July 1st issue of the Journal of Clinical Oncology.

‘Combination therapies,’ lead investigator Dr. Jalid Sehouli told Reuters Health, ‘were associated with higher toxicity, but progression-free survival and overall survival were not significantly different.’

Dr. Sehouli, of Humboldt University in Berlin, and colleagues explain in their paper that although topotecan monotherapy is an established treatment, there was evidence to suggest that combination therapy may provide better results.

To investigate further, the researchers studied 502 women in whom ovarian cancer recurred following primary surgery and platinum-based chemotherapy. They were randomized to receive either topotecan alone or in combination with etoposide or gemcitabine.

Median overall survival was not significantly different among the groups: 17.2 months with topotecan alone, 17.8 months with the etoposide combination and 15.2 months with the gemcitabine combination. There were no differences in either median progression-free survival or objective response rates.

The researchers note that the incidence of thrombocytopenia was lower with monotherapy (13.5%) than with the etoposide combination (21.5%) or gemcitabine combination (31.3%), and they conclude that combination therapy increases toxicity and does not provide a survival advantage.

‘Based on our results,’ Dr. Sehouli warns, ‘physicians should not harm their patients with such combination regimens.’”

Quoted Source: Topotecan Combo No Extra Help in Ovarian Cancer, by David Douglas, Matria Healthcare News, July 28, 2008 (summarizing the findings of Nonplatinum topotecan combinations versus topotecan alone for recurrent ovarian cancer: results of a phase III study of the North-Eastern German Society of Gynecological Oncology Ovarian Cancer Study Group; Sehouli J et. al., J Clin Oncol. 2008 July;26(19):3176-82.

Additional Information:

From Zero to Hero: HMGB1 Protein Found to Promote DNA Repair, Prevents Cancer

“An abundant chromosomal protein [HMGB1] that binds to damaged DNA prevents cancer development by enhancing DNA repair, researchers at The University of Texas M. D. Anderson Cancer Center report online this week in the Proceedings of the National Academies of Science.”

“An abundant chromosomal protein that binds to damaged DNA prevents cancer development by enhancing DNA repair, researchers at The University of Texas M. D. Anderson Cancer Center report online this week in the Proceedings of the National Academies of Science.

The protein, HMGB1 [High mobility group box 1] , was previously hypothesized to block DNA repair, said senior author Karen Vasquez, Ph.D., associate professor in M. D. Anderson’s Department of Carcinogenesis at the Science Park – Research Division in Smithville, Texas.

Identification and repair of DNA damage is the frontline defense against the birth and reproduction of mutant cells that cause cancer and other illnesses.

Pinpointing HMGB1’s role in repair raises a fundamental question about drugs under development to block the protein, Vasquez said. The protein also plays a role in inflammation, so it’s being targeted in drugs under development for rheumatoid arthritis and sepsis.

‘Arthritis therapy involves long-term treatment,’ Vasquez said. ‘Our findings suggest that depleting this protein may leave patients more vulnerable to developing cancer.’

Long known to attach to sites of damaged DNA, the protein was suspected of preventing repair. ‘That did not make sense to us, because HMGB1 is a chromosomal protein that’s so abundant that it would be hard to imagine cell repair happening at all if that were the case,’ Vasquez said.

In a series of experiments reported in the paper, Vasquez and first author Sabine Lange, a doctoral candidate in the Graduate School of Biomedical Sciences, tracked the protein’s impact on all three steps of DNA restoration: access to damage, repair and repackaging of the original structure, a combination of DNA and histone proteins called chromatin.

First, they knocked out the [HMGB1] gene in mouse embryonic cells [HMGB1 knockout cells] and then exposed cells to two types of DNA-damaging agents. One was UV light, the other a chemotherapy called psoralen that’s activated by exposure to darker, low frequency light known as UVA. In both cases, the cells survived at a steeply lower rate after DNA damage than did normal cells.

Next they exposed HMGB1 knockout cells and normal cells to psoralen and assessed the rate of genetic mutation. The knockout cells had a mutation frequency more than double that of normal cells, however, there was no effect on the types of mutation that occurred.

Knock out and normal cells were then exposed to UV light and suffered the same amount of damage. However, those with HMGB1 had two to three times the repair as those without. Evidence suggests that HMGB1 works by summoning other DNA repair factors to the damaged site, Vasquez said.

The last step in DNA repair is called chromatin remodeling. DNA does not exist in a linear structure in the chromosome, but wraps around specialized histone proteins. This chromatin structure permits access to DNA when it is loose, or opened up, and blocks access when it is more tightly wrapped. Presence of HMGB1 resulted in a much higher rate of chromatin assembly in both undamaged and UVC-damaged cells.

Lange and Vasquez hypothesize that HMGB1 normally binds to the entrance and exit of DNA nucleosomes, so is nearby when DNA damage occurs. It then binds to and bends the damaged site at a 90-degree angle, a distortion that may help DNA repair factors recognize and repair the damage. After repair it facilitates restructuring of the chromatin.

Co-author with Lange and Vasquez is David Mitchell, Ph.D., professor of carcinogenesis.

The research was supported by grants from the National Cancer Institute and the National Institute of Environmental Health Sciences as well as an American Legion Auxiliary fellowship. 07/21/08”

Quoted Source: Once Suspect Protein Found to Promote DNA Repair, Prevent Cancer – M. D. Anderson scientists caution against targeting HMGB1 to treat other disease, M. D. Anderson News Release, July 21, 2008.

M.D. Anderson Identifies TG2 As a Potential Target in Chemo-Resistant Ovarian Cancer

“Scientists from The University of Texas M. D. Anderson Cancer Center have found overexpression of tissue type transglutaminase (TG2) in ovarian cancer is associated with increased tumor cell growth and adhesion, resistance to chemotherapy and lower overall survival rates. When researchers targeted and silenced TG2 in animal models, cancer progression was reversed, suggesting the protein may also provide a novel therapeutic approach for late-stage ovarian cancer.”

“Scientists from The University of Texas M. D. Anderson Cancer Center have found overexpression of tissue type transglutaminase (TG2) in ovarian cancer is associated with increased tumor cell growth and adhesion, resistance to chemotherapy and lower overall survival rates. When researchers targeted and silenced TG2 in animal models, cancer progression was reversed, suggesting the protein may also provide a novel therapeutic approach for late-stage ovarian cancer.

These findings in the July 15th issue of Cancer Research by a team of researchers led by Anil K. Sood, M.D., professor in the Departments of Gynecologic Oncology and Cancer Biology, and Kapil Mehta, Ph.D., professor in the Department of Experimental Therapeutics at M. D. Anderson, are among the first to explore TG2’s functionality in ovarian cancer.

‘TG2 appears to fuel different types of cancer through multiple molecular pathways, making it an important therapeutic target,’ said Mehta, whose lab also has connected TG2 overexpression to drug-resistant and metastatic melanoma, breast cancer and pancreatic cancer.

‘Drug resistance and metastasis are major impediments to the successful treatment of ovarian cancer and until now we had little information about the role TG2 played in ovarian cancer,’ Sood said. ‘We began to see its story unfold as we translated this data from tissue samples to cell lines to animal models.’

The American Cancer Society estimates 15,000 U.S. women will die from ovarian cancer this year. Most patients present with advanced stage disease that has spread beyond the primary tumor site. More than 70 percent of ovarian cancer patients will suffer a recurrence and eventually succumb to the disease.

Higher TG2, lower survival

The study, which examined 93 ovarian cancer samples of ranging stages, found that high levels of TG2 corresponded with significantly lower patient survival than those with low levels of TG2. Sixty-nine percent of high-stage ovarian cancers overexpressed TG2 compared with 30 percent of low-stage cancers. In-depth analysis demonstrated that tumors which overexpressed the protein tended to have an increased ability to invade healthy tissue and to survive or avoid the affects of chemotherapy.

‘From this investigation it became clear that TG2 activates the survival pathway p13K/Akt in these tumors, explaining the adverse, resistant behavior we observed on a molecular level,’ said Sood. ‘We then focused on whether silencing TG2 would block these effects.’

Researchers shut off TG2 with a small interfering RNA strand (TG2 siRNA) targeted to the protein, reducing the ability of the tumor cells to invade and killing them through programmed cell death, or apoptosis. ‘When exposed to this potent targeted therapy, ovarian cancer cells greatly reduced cancer cell proliferation and blood vessel development, while increasing apoptosis,’ said Sood.

Mouse model studies of chemotherapy-sensitive and chemotherapy-resistant models showed considerable antitumor activity both with TG2 siRNA alone and in combination with docetaxel chemotherapy. The combination therapy of TG2 siRNA with docetaxel reduced tumor weight by 86 percent, proving to have the greatest efficacy compared to control groups or those without chemotherapy.

‘While it remains to be seen if these results will translate in humans, looking ahead long term, it will be an attractive option against advanced ovarian cancer,’ said co-author Gabriel Lopez-Berestein, M.D. professor in the Department of Experimental Therapeutics at M. D. Anderson.

TG2 fuels pancreatic cancer differently

Sood and Lopez-Berestein, have developed siRNA therapy by packaging the gene-silencing strips of RNA in a fatty nanoparticle called a liposome and delivering it intravenously. TG2 is the third protein they have targeted in preclinical research. Sood and Mehta are moving TG2 siRNA toward Phase I clinical trials for ovarian and pancreatic cancers.

TG2 acts through different pathways in other types of cancer, Mehta noted. For example, TG2 overexpression causes the degradation of the tumor-suppressing protein PTEN in pancreatic cancer, Mehta and colleagues reported in Clinical Cancer Research in April. With PTEN out of the picture, pancreatic cancer is protected from a separate type of cell death called autophagy. In a separate paper, they showed that silencing TG2 with the siRNA liposome reduced tumor size, slowed metastasis and enhanced the effect of gemcitabine chemotherapy.

‘This aberrant protein is doing so many different things, you would have to develop a small-molecule drug to block each function,’ Mehta said. ‘Liposomal siRNA is exciting because it takes out TG2 completely, blocking everything that it does.’

Research was funded by grants from the National Cancer Institute, including M. D. Anderson’s Specialized Program in Research Excellence in Ovarian Cancer grant, a program project development grant from the Ovarian Cancer Research Fund, Inc., and the Zarrow Foundation.

In addition to Sood, Mehta and Lopez-Berestein, authors include Jee Young Hwang, M.D., Lingegowda S. Mangala, Ph.D., co-first authors, and Yvonne G. Lin, M.D., William M. Merritt, M.D., Whitney A. Spannuth, M.D., Alpa M. Nick, M.D., Derek J. Fiterman, M.D., and Robert L. Coleman, M.D., all of M. D. Anderson’s Department of Gynecologic Oncology; Jansina Y. Fok, also a co-first author, and Pablo E. Vivas-Mejia, Ph.D., both of the Department of Experimental Therapeutics; and Michael T. Deavers, M.D., of M. D. Anderson’s Department of Pathology. Hwang is also with the Department of Obstetrics and Gynecology, Dongguk University of College of Medicine, Kyung-ju, Korea. 07/15/08”

Quoted Source: TG2 Identified as Potential Target in Chemo-Resistant Ovarian Cancer – M. D. Anderson team silences protein with siRNA, implicates TG2 in fourth cancer, The University of Texas, M.D. Anderson Cancer Center News Release, July 15, 2008 (summarizing the findings of Clinical and biological significance of tissue transglutaminase in ovarian carcinoma; Sood, AK et. al,  Cancer Res. 2008 Jul 15;68(14):5849-58.)

Additional Information:

Vermillion Files FDA Pre-Market Application for OVA1 Ovarian Tumor Triage Test

” …The OVA1 [Ovarian Tumor Triage Test] test will help assess the risk of malignancy in the hundreds of thousands of women who require surgery for ovarian tumors each year. ‘This information can be used to identify those who might benefit from referral to a gynecologic oncologist,’ said Fred Ueland, M.D., principal investigator of the study and Associate Professor of Gynecologic Oncology at the University of Kentucky. While most tumors are benign, numerous studies have shown that women with ovarian cancer have better overall outcomes when their surgery is performed by a gynecologic oncologist.”

FREMONT, Calif., June 25 /PRNewswire-FirstCall/ — Vermillion, Inc. (Nasdaq: VRML), a molecular diagnostics company, today announced that it has submitted a 510(k) pre-market notification application to the U.S. Food & Drug Administration (FDA) requesting regulatory clearance of its Ovarian Tumor Triage Test known as OVA1™.

As announced previously, the OVA1 prospective clinical trial met its primary endpoints, indicating that the test is capable of stratifying women with pelvic masses into high- and low-risk categories to help determine whether the patient should be referred to a specialist prior to surgery. The clinical trial was one of the largest ovarian cancer studies ever conducted and assessed more than 550 women with a confirmed adnexal mass at 27 clinical sites in the United States. Additionally, the trial was the culmination of more than eight independent studies in more than 2,500 women.

The OVA1 test will help assess the risk of malignancy in the hundreds of thousands of women who require surgery for ovarian tumors each year. ‘This information can be used to identify those who might benefit from referral to a gynecologic oncologist,’ said Fred Ueland, M.D., principal investigator of the study and Associate Professor of Gynecologic Oncology at the University of Kentucky. While most tumors are benign, numerous studies have shown that women with ovarian cancer have better overall outcomes when their surgery is performed by a gynecologic oncologist.

This is an important milestone for Vermillion and a significant step toward the commercialization of OVA1™. ‘We are pleased with the results of the trial and look forward to discussing the significance of our data and our commercialization strategy in an upcoming investor roundtable, planned for July,’ said Gail Page, President and CEO of Vermillion. ‘We also look forward to receiving regulatory clearance from the FDA and making OVA1 available to the hundreds of thousands of women who could benefit considerably from the test.’

Vermillion will host a roundtable teleconference to address the need for OVA1 on Tuesday, July 15. Fred Ueland, M.D., principal investigator of the OVA1 clinical study, will serve as the keynote speaker. Conference call details, including dial-in information and timing, are forthcoming.

About Vermillion’s Ovarian Cancer Diagnostic Program

In addition to developing a diagnostic test designed to distinguish between benign and malignant pelvic masses, Vermillion has a broad program of ovarian cancer diagnostic tests in development. Studies are underway to validate diagnostic tests developed to detect early-stage ovarian cancer, predict prognosis and recurrence, and identify women considered at high-risk for the disease.

Vermillion’s comprehensive diagnostic development program is being conducted with several leading collaborators at The Johns Hopkins School of Medicine, The University of Texas M.D. Anderson Cancer Center, Rigshospitalet (Copenhagen), and the University of Kentucky.

The Company’s OVA1 test is part of a strategic alliance with Quest Diagnostics to jointly develop and commercialize diagnostic tests.

About Vermillion

Vermillion, Inc. is dedicated to the discovery, development and commercialization of novel high-value diagnostic tests that help physicians diagnose, treat and improve outcomes for patients. Vermillion, along with its prestigious scientific collaborators, has diagnostic programs in oncology, hematology, cardiology and women’s health. Vermillion is based in Fremont, California. Additional information about Vermillion can be found on the Web at http://www.vermillion.com.”

[Quoted Source: Vermillion Files 510(k) Application With U.S. Food & Drug Administration for OVA1 Ovarian Tumor Triage Test – Significant Milestone Achieved Based on Compelling Clinical Studies, Vermillion, Inc. Press Release, June 25, 2008.]

Additional Information:  To learn more about molecular diagnostics and proteomics, see Understanding Cancer Series: Molecular Diagnostics, National Cancer Institute, September 1, 2006.

Webcast: Recognizing and Overcoming Challenges in the Treatment of Recurrent Ovarian Cancer

Maurie Markman, M.D. is the Vice President for Clinical Research at the University of Texas M.D. Anderson Cancer Center located in Houston, Texas. On June 6, 2008, Dr. Markman moderated an expert panel discussion entitled, “Recognizing and Overcoming Challenges in the Treatment of Recurrent Ovarian Cancer.” The panel discussion was recorded as a Continuing Medical Education (CME) webcast. The two doctors participating in the panel discussion with Dr. Markman are (i) William P. McGuire, MD, the Medical Director of the Harry and Jeanette Weinberg Cancer Institute at the Franklin Square Hospital Center, located in Baltimore, Maryland, and (ii) Robert L. Coleman, MD, professor of gynecological oncology at the University of Texas M. D. Anderson Cancer Center.

The expert panel discussion was divided into the two sessions listed below. Click here if you are interested in watching the webcast version of each session. A transcript of each session is also provided below.