Ovarian Cancer Tumors Can Grow For Ten Years Or More Before Being Detected By Today’s Blood Tests

A new mathematical model developed by Stanford University School of Medicine scientists finds that ovarian cancer tumors can grow for 10 years or longer before currently available blood tests will detect them.

A new mathematical model developed by Stanford University School of Medicine scientists indicates that tumors can grow for 10 years or longer before currently available blood tests will detect them. The analysis, which was restricted to ovarian cancer tumors but is broadly applicable across all solid tumor types, was published online November 16 in Science Translational Medicine.

“The study’s results can be viewed as both bad and good news,” said Sanjiv “Sam” Gambhir, M.D., Ph.D., professor and chair of radiology and the study’s senior author. Sharon Hori, Ph.D., a postdoctoral scholar in Dr. Gambhir’s laboratory, is the lead study author.

The mathematical model developed by Dr. Sam Gambhir’s lab shows that it would be possible to detect tumors years before they grow big enough to metastasize if researchers can develop the right biomarkers.

The bad news, as explained by Dr. Gambhir, is that by time a tumor reaches a detectable size using today’s available blood tests, it is likely to have metastasized to other areas of the body, making it much more deadly than if it had been caught earlier. “The good news is that we have, potentially, 10 or even 20 years to find the tumor before it reaches this size, if only we can improve our blood-based methods of detecting tumors,” said Dr. Gambhir. “We think our mathematical model will help guide attempts to do that.”

The study advances previous research about the limits of current detection methods. For instance, it is strikingly consistent with a finding reported two years ago by Stanford biochemistry professor Patrick Brown, M.D., Ph.D., that current ovarian cancer tests could not detect tumors early enough to make a significant dent in the mortality rate. There is a push to develop more-sensitive diagnostic tests and find better biomarkers, and Dr. Gambhir’s new model could be an essential tool in this effort. For the first time, the new model connects the size of a tumor with blood biomarker levels being shed by that tumor.

To create their model, Drs. Gambhir and Hori used mathematical models originally developed to predict the concentration of drugs injected into the blood. The investigators linked these to additional models of tumor cell growth.

Tumors do not secrete drugs, but they can shed telltale molecules into surrounding tissue, from which those substances, known as “biomarkers,” diffuse into the blood. Some biomarkers may be made predominantly by tumor cells.  These substances can be measured in the blood as proxies for a tumor.

Some biomarkers are in wide use today. One is the well-known PSA (prostate specific antigen) for prostate cancer. Another example of a biomarker is CA-125 (cancer antigen 125) for ovarian cancer. But these and other currently used blood tests for cancer biomarkers were not specifically developed for early detection, and are generally more effective for relatively noninvasive monitoring of the progress of a late-stage tumor or tumor response to treatment. That is, rising blood levels of the substance may indicate that the tumor is growing, while declining levels may indicate possible tumor shrinkage.

Both CA-125 and PSA are also produced, albeit in smaller amounts, by healthy tissue, complicating efforts to detect cancer at an early stage when the tumor’s output of the biomarker is relatively low.

The new mathematical model employs separate equations, each governing the movement of a biomarker from one compartment into the next. Into these equations, one can plug known values — such as how fast a particular type of tumor grows, how much of the biomarker a tumor cell of this type sheds per hour, and the minimum levels of the biomarker that must be present in the blood for a currently available assay to detect it.

As a test case, Drs. Gambhir and Hori chose CA-125, a well-studied biomarker which is shed into the blood by ovarian cancer tumors. Ovarian cancer is a notorious example of a condition for which early detection would make a significant difference in survival outcomes.

CA-125 is a protein made almost exclusively by ovarian tumor cells. The well-known pharmacokinetics, metabolic fates (typical amounts secreted by an ovarian cell), typical ovarian tumor growth rates, and other properties of CA-125 make the biomarker an excellent candidate for “road testing” with Gambhir and Hori’s model. CA-125 is by no means the ideal biomarker, said Dr. Gambhir, while noting that it can still be used to better understand the ideal properties of biomarkers for early ovarian cancer detection.

Applying their equations to CA-125, Drs. Gambhir and Hori determined that an ovarian cancer tumor would need to reach a size of approximately 1.7 billion cells, or the volume of a cube with a 2-centimeter edge, before the currently available CA-125 blood test could reliably detect it. At typical tumor-growth rates, it would take a single cancer cell approximately 10.1 to 12.6 years of development to become a tumor containing 1.7 billion cells.

The model further calculated that a biomarker otherwise equivalent to CA125 — but shed only by ovarian tumor cells — would allow reliable detection within 7.7 years, while the tumor’s size would be that of a tiny cube about one-sixth of an inch high.

In the last decade, many potential new biomarkers for different forms of cancers have been identified. There’s no shortage of promising candidates — six for lung cancer alone, for example. But validating a biomarker in large clinical trials is a long, expensive process. So it is imperative to determine as efficiently as possible which, among many potential tumor biomarkers, is the best prospective candidate.

“This [mathematical] model could take some of the guesswork out of it,” Gambhir said. He also stated:

“It [the mathematical model] can be applied to all kinds of solid cancers and prospective biomarkers as long as we have enough data on, for instance, how much of it a tumor cell secretes per hour, how long the biomarker can circulate before it’s degraded and how quickly tumor cells divide. We can tweak one or another variable — for instance, whether a biomarker is also made in healthy tissues or just the tumor, or assume we could manage to boost the sensitivity of our blood tests by 10-fold or 100-fold — and see how much it advances our ability to detect the tumor earlier on.”

There are new detection technologies capable of detecting biomarkers at concentrations as low as a few hundred molecules per milliliter (1-cubic centimeter) of blood. In 2009, Dr. Gambhir and his colleagues reported on one such developing technology: “magneto-nanosensors” that can detect biomarkers with a 100-fold greater sensitivity than current methods.

Better biomarker detection alone might allow ovarian cancer tumor detection at the 9-year point, said Gambhir.

A second priority is to come up with new and better biomarkers. “It’s really important for us to find biomarkers that are made exclusively by tumor cells,” Dr. Gambhir said.

Under the right conditions (a highly sensitive assay measuring levels of a biomarker that is shed only by cancer cells), Gambhir stated, the model predicts that a tiny tumor with a volume equivalent to a cube less than one-fifteenth of an inch (or 1.7 millimeters) on a side could be detected.

Dr. Gambhir is also the Virginia and D.K. Ludwig Professor in Cancer Research and director of the Molecular Imaging Program at Stanford, the director of the Canary Center at Stanford for Cancer Early Detection, and a member of the Stanford Cancer Institute.

The study was funded by the Canary Foundation and the National Cancer Institute.

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Exelixis Reports Promising Interim Data From Ovarian Cancer Patients Treated With XL184

Exelixis reports promising interim data from ovarian cancer patients treated with XL184, including:  a  32% confirmed response rate per RECIST in patients with platinum-resistant or platinum-sensitive disease, and a 64% overall week-12 disease control rate.

Ignace Vergote, M.D., Ph.D., Head, Department of Obstetrics & Gynecology and Gynecologic Oncology, Catholic University Hospital, Leuven, Belgium

Exelixis, Inc.  today reported interim data from the cohort of patients with advanced epithelial ovarian cancer, primary peritoneal, or fallopian tube carcinoma treated with XL184 in an ongoing phase 2 adaptive randomized discontinuation trial (RDT) [1]. Ignace Vergote, M.D., Ph.D., Head of the Department of Obstetrics and Gynecology and Gynecologic Oncology at the Catholic University Hospital Leuven, Leuven, Belgium, will present the data in the Molecular-Targeted Therapies-Clinical Trials poster session (Abstract #407) on Thursday, November 18th, at the 22nd EORTC-NCI-AACR [2] Symposium on Molecular Targets and Cancer Therapeutics, being held in Berlin, Germany.

XL184 Activity in Patients with Ovarian Cancer

XL184 is an oral, potent inhibitor of MET, VEGFR2 and RET. MET overexpression has been observed in advanced ovarian cancer, and anti-VEGF pathway agents have shown clinical benefit in ovarian cancer patients. For these reasons, co-targeting of the MET and VEGF signaling pathways using XL184 may represent a promising treatment strategy.

As of the November 1, 2010 cut-off date, a total of 51 patients were enrolled into the ovarian cancer cohort, with 31 evaluable for response, and 41 evaluable for safety. The median number of prior systemic treatments was 2. Tumor shrinkage was observed in 30 of 37 (81%) patients with measurable metastatic lesions. Of 31 patients evaluable for response per RECIST (Response Evaluation Criteria In Solid Tumors), 10 (32%) achieved a confirmed partial response (PR). Stable disease (SD) was reported in 15 patients (48%) including 3 patients who achieved unconfirmed PRs. The overall week-12 disease control rate (DCR)(complete responses + partial responses + stable disease responses = DCR) was 64%.

Upon subset analysis, 5 of 17 platinumrefractory or –resistant patients (29%) evaluable for response per RECIST achieved a confirmed PR. SD was reported in 7 patients (41%) including 2 patients with unconfirmed PRs. The week-12 DCR was 59% in platinum-resistant/refractory patients. Durable responses have been observed, including 2 patients with platinum-refractory or resistant disease who remain on study for 34+ and 36+ weeks, and 3 patients with platinum-sensitive disease on study for 24, 24+, and 28+ weeks. Some patients have experienced reductions in the ovarian cancer blood marker CA125, but in general no clear concordance between CA125 changes and tumor shrinkage has been observed.

Safety data are available for 49 patients who had at least 6 weeks of follow-up. The most common grade greater-than or equal to 3 adverse events, regardless of causality were PPE (Palmar-Plantar Erythrodysesthesia) syndrome (also referred to as “hand-foot syndrome”) (12%), diarrhea (7%), fatigue, vomiting (each 5%), nausea, rash, abdominal pain, hypertension, and hypomagnesemia (each 2%).

“The activity of XL184 in women with both platinum-sensitive and platinum-resistant/refractory disease is unique and encouraging. The response rate and overall disease control rate of this oral agent are impressive especially in the group of patients with platinum refractory/resistant ovarian cancer, and compare favorably to other targeted and systemic agents in development,” said, Dr. Vergote. “I believe these encouraging data warrant further evaluation of XL184 in ovarian cancer.”

Michael M. Morrissey, Ph.D., President & Chief Executive Officer, Exelixis, Inc.

“The high response rate in patients with ovarian cancer is reflective of the broad anti-tumor activity of XL184 observed in multiple tumor types to date,” said Michael M. Morrissey, Ph.D., president and chief executive officer of Exelixis. “The data from the RDT underscore the novel and differentiated clinical activity of XL184 in diverse tumor indications with predominance of either soft tissue or bone involvement.”

To access the clinical data poster mentioned in this press release, please visit www.exelixis.com.

Broad Clinical Activity of XL184 – Randomized Discontinuation Trial

XL184 has demonstrated anti-tumor activity in 9 of 12 indications studied to date. In ongoing trials, compelling activity has been observed in medullary thyroid cancer, glioblastoma, and clear cell renal cancer. In the RDT, XL184 is being evaluated in nine different tumor types, with clear signals of activity in six: prostate, ovarian, hepatocellular, breast, non-small cell lung cancer and melanoma. The adaptive RDT design allowed for rapid simultaneous assessment of the activity of XL184 across nine different tumor indications. As of the November 1, 2010 cut-off date, a total of 397 patients have been enrolled into the nine disease-specific cohorts, with 273 evaluable for response, and 312 evaluable for safety. Of 273 patients evaluable for response per RECIST, 39 achieved a PR (either confirmed or unconfirmed) and 100 had SD at week 12. The week-12 DCR for the overall population was 49%, with the highest rates occurring in hepatocellular cancer (75%), castration-resistant prostate cancer (71%), ovarian cancer (64%), melanoma (45%), non-small cell lung cancer (42%) and breast cancer (42%). Of note, a breast cancer patient with evidence of bone metastasis on bone scan demonstrated evidence of resolution on bone scan accompanied by 29% reduction in tumor size. XL184 has been generally well tolerated with a consistent adverse event profile across the nine different RDT tumor types.

About XL184

XL184, an inhibitor of tumor growth, metastasis and angiogenesis, simultaneously targets MET and VEGFR2, key kinases involved in the development and progression of many cancers, including ovarian cancer. It has recently been shown in preclinical models that treatment with selective inhibitors of VEGF signaling can result in tumors that are more invasive and aggressive compared to control treatment. In preclinical studies, upregulation of MET has been shown to occur in concert with development of invasiveness after selective anti-VEGF therapy, and may constitute a mechanism of acquired or evasive resistance to agents that target VEGF signaling. Accordingly, treatment with XL184 in similar preclinical studies resulted in tumors that were less invasive and aggressive compared to control or selective anti-VEGF treatment. Therefore, XL184 has the potential for improving outcomes in a range of indications, including those where selective anti-VEGF therapy has shown minimal or no activity.

About Exelixis

Exelixis, Inc. is a development-stage biotechnology company dedicated to the discovery and development of novel small molecule therapeutics for the treatment of cancer. The company is leveraging its biological expertise and integrated research and development capabilities to generate a pipeline of development compounds with significant therapeutic and commercial potential for the treatment of cancer. Currently, Exelixis’ broad product pipeline includes investigational compounds in phase 3, phase 2, and phase 1 clinical development. Exelixis has established strategic corporate alliances with major pharmaceutical and biotechnology companies, including Bristol-Myers Squibb Company, sanofi-aventis, GlaxoSmithKline, Genentech (a wholly owned member of the Roche Group), Boehringer Ingelheim, and Daiichi-Sankyo. For more information, please visit the company’s web site at http://www.exelixis.com.

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1/Rosner GL, Stadler W, Ratain MJ. et. al.  Randomized discontinuation design: Application to cytostatic antineoplastic agents. J Clin Oncol 20:4478-4484, 2002.  Pursuant to this design, all patients receive the investigational drug for an initial period of time. Patients with standard radiologic tumor shrinkage within that timeframe would continue investigational therapy, while those with radiologic progression or unacceptable toxicity would discontinue therapy. All patients with radiologic stable disease after the initial therapy period are then randomized to continuing or discontinuing therapy in a double-blind placebo-controlled manner. This is an enrichment strategy in which patients with the end point of interest are preferentially enrolled in the randomized portion and in which the heterogeneity of the randomized population is decreased. These two factors result in an increased power for detecting a clinically relevant difference and decrease the number of patients exposed to placebo. Importantly, the enrichment is driven by the properties of the investigational drug as opposed to clinical prognostic factors identified in historical untreated patients or patients treated with a different class of agents. In addition, the statistical behavior of the trial is not highly dependent on investigators’ assumptions regarding the “no dose effect” (i.e., non-receipt of drug = no effect)  for time to progression or stable disease rate, and thus effectively deals with uncertainty in this variable. Finally, patients may find such a trial design more appealing, resulting in brisk accrual.

2/EORTC [European Organisation for Research and Treatment of Cancer, NCI [National Cancer Institute], AACR [American Association for Cancer Research].

PARP Inhibitor MK-4827 Shows Anti-Tumor Activity in First Human Clinical Study

MK-4827, a new drug that targets proteins responsible for helping cancer cells repair their damaged DNA, has shown promising anti-tumor activity in its first human clinical trial.

MK-4827, a new drug that targets proteins responsible for helping cancer cells repair their damaged DNA, has shown promising anti-tumour activity in its first human clinical trial. Some patients with a range of solid tumors, many of whom had been treated unsuccessfully for their cancer with other therapies, have seen their tumors shrink or stabilize for periods of between 46 days to more than a year. The research will be presented today (Thursday) at the 22nd EORTCNCIAACR [1] Symposium on Molecular Targets and Cancer Therapeutics, which is being held in Berlin, Germany.

PARP is a key signaling enzyme involved in triggering the repair of single-strand DNA damage. PARP inhibition has been demonstrated to selectively kill tumor cells lacking components of the homologous recombination (HR) DNA repair pathway while sparing normal cells. Known defects in HR repair include the well-characterized hereditary BRCA1 and BRCA2 mutations in breast and ovarian cancer, as well as nonhereditary BRCA mutations. (Photo Credit: AstraZeneca Oncology)

Laboratory studies of the drug, MK-4827, have shown that it inhibits proteins called PARP1 and PARP2 (poly(ADP)-ribose polymerase). PARP is involved in a number of cellular processes and one of its important functions is to assist in the repair of single-strand breaks in DNA. Notably, if one single-strand DNA break is replicated (replication occurs before cell division), then it results in a double-strand break.  By inhibiting the action of PARP, double-strand breaks occur, which in turn, lead to cell death. Tumors that are caused by a mutation in the BRCA1 or BRCA2 genes are susceptible to cell death through PARP inhibition because correctly functioning BRCA genes assist in repairing double-strand DNA breaks via a process called homologous-recombination-dependent DNA repair, whereas mutated versions are unable to perform this role. Normal cells do not replicate as often as cancer cells and they still have homologous repair operating; this enables them to survive the inhibition of PARP and makes PARP a good target for anti-cancer therapy.

In a Phase I trial [2] conducted at the H. Lee Moffitt Cancer Center (Tampa Florida, USA), University of Wisconsin-Madison (Madison, USA) and the Royal Marsden Hospital (London, UK), MK-4827 was given to 59 patients (46 women, 13 men) with a range of solid tumors such as non-small cell lung cancer (NSCLC), prostate cancer, sarcoma, melanoma and breast and ovarian cancers. Some patients had cancers caused by mutations in the BRCA1/2 genes, such as breast and ovarian cancer, but others had cancers that had arisen sporadically.

Robert M. Wenham, M.D., MS, FACOG, Clinical Director, Gynecologic Oncology, Department of Women's Oncology, H. Lee Moffitt Cancer Center

The drug was given in pill form once a day, and the researchers found that the maximum tolerated dose was 300 mg per day. Dr. Robert Wenham, Clinical Director for Gynecologic Oncology in the Department of Women’s Oncology at the Moffitt Cancer Center, who is presenting data on behalf of the participating investigators, said: “MK-4827 is generally well tolerated, with the main dose-limiting toxicity being thrombocytopenia – an abnormal decrease in the number of platelets in the circulatory blood. The most common side effects are mild nausea, vomiting, anorexia and fatigue.”

The researchers saw anti-tumor responses in both sporadic (non-inherited) and BRCA1/2 mutation-associated cancers [emphasis added]. Ten patients with breast and ovarian cancers had partial responses, with progression-free survival between 51-445 days, and seven of these patients are still responding to treatment. Four patients (two with ovarian cancer and two with NSCLC) had stable disease for between 130-353 days.

Dr. Wenham said: “Most patients in the trial had exhausted standard therapies and those who responded to this drug have benefited. Several patients have been receiving treatment for more than a year. The responses mean that MK-4827 is working as hoped and justify additional studies. Just how well MK-4827 works compared to other treatments is the goal of the next set of studies.”

He gave a possible explanation as to why patients with cancers that were not caused by BRCA1 or BRCA 2 gene mutations also responded to the PARP inhibition. “BRCA is a tumor suppressor gene that assists in repairing double stranded DNA breaks. In BRCA-mutation related cancers, loss of both copies of the gene results in a non-functional protein and thus BRCA deficiency. Because BRCA works with other proteins, BRCA-pathway related deficiency can be seen in the absence of two mutated copies of the BRCA genes. This may explain why responses have been reported for this class of drugs in non-BRCA mutant cancers.”

Dr. Wenham and his colleagues are recruiting more patients for additional studies and an expansion of the existing trial. “We want to understand what types of cancers will respond best to treatment with MK-4827,” he said. “Cohorts are currently open for patients with ovarian cancer, patients without germ-line BRCA mutations, and prostate cancer patients. Cohorts will open soon for patients with T-cell prolymphocytic leukemia, endometrial cancer, breast cancer and colorectal cancer. MK-4827 is also being studied in combination with conventional chemotherapy drugs.”

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Additional Information:

Related Information:

References:

[1] EORTC [European Organisation for Research and Treatment of Cancer, NCI [National Cancer Institute], AACR [American Association for Cancer Research].

[2] This study was funded by Merck & Co., Inc. MK-4827 is owned by Merck & Co., Inc.

Dana-Farber Researchers “OncoMap” The Way To Personalized Treatment For Ovarian Cancer

Researchers have shown that point mutations – mis-spellings in a single letter of genetic code – that drive the onset and growth of cancer cells can be detected successfully in advanced ovarian cancer using a technique called OncoMap. The finding opens the way for personalized medicine in which every patient could have their tumor screened, specific mutations identified, and the appropriate drug chosen to target the mutation and halt the growth of their cancer.

Researchers have shown that point mutations – mis-spellings in a single letter of genetic code – that drive the onset and growth of cancer cells can be detected successfully in advanced ovarian cancer using a technique called OncoMap. The finding opens the way for personalized medicine in which every patient could have their tumor screened, specific mutations identified, and the appropriate drug chosen to target the mutation and halt the growth of their cancer.

Using mass spectrometry for identifying the genetic make-up of cancer cells, OncoMap can determine the point mutations in tumors by utilizing a large panel of over 100 known cancer-causing genes (referred to as “oncogenes“). In the work to be presented today (Wednesday) at the 22nd EORTCNCIAACR [1] Symposium on Molecular Targets and Cancer Therapeutics in Berlin, researchers will describe how they used OncoMap to identify oncogene mutations in tumor samples obtained from women with advanced high-grade serous ovarian cancer. [2] Earlier in the year 76 mutations in 26 different genes had been found but, since then, further work in more tumor samples has found more.

Ursula A. Matulonis, M.D., Medical Director, Gynecologic Oncology, Dana-Farber Cancer Institute; Associate Professor, Medicine, Harvard Medical School

Dr. Ursula Matulonis, director/program leader in medical gynecologic oncology at the Dana-Farber Cancer Institute located in Boston, Massachusetts (USA) and Associate Professor of Medicine at Harvard Medical School, will tell the meeting:

“Epithelial ovarian cancer is the most lethal of all the gynecologic malignancies, and new treatments are needed for both newly diagnosed patients as well as patients with recurrent cancer. The success of conventional chemotherapy has reached a plateau, and new means of characterizing ovarian cancer so that treatment can be personalized are needed.

We know that many human cancers have point mutations in certain oncogenes, and that these mutations can cause cancer cells to have a dependence on just one overactive gene or signalling pathway for the cancer cell’s growth and survival – a phenomenon known as ‘oncogene addiction’. If the mutation that causes the oncogene addiction can be inhibited, then it seems that this often halts the cancer process. Examples of mutations that are successfully inhibited by targeted drugs are HER2 (for which trastuzumab [Herceptin®] is used in breast cancer), EGFR (erlotinib [Tarceva®] in lung cancer) and c-kit (imatinib [Gleevec®] in chronic myeloid leukemia). So if we know the status of specific genes in a tumor, then this enables us to choose specific treatments that are likely to work successfully against the cancer.”

Dr Matulonis and her colleagues used OncoMap to investigate the mutation status of high-grade serous ovarian tumors that were known not to be caused by inherited mutations in the BRCA 1 and BRCA 2 genes. They found mutations previously identified to be involved in ovarian cancer: KRAS, BRAF, CTNNB1 and PIK3CA. The KRAS and PIK3CA mutations were the most common, while BRAF was more rare. The researchers also identified a low frequency of mutations in many other different oncogenes.

Dr. Matulonis further noted:

“This study shows that it’s feasible to use OncoMap to identify whether a patient’s tumor has a mutation in an oncogene for which a known drug is available to target that specific gene, so as to enable us to place her on a clinical study of that drug; for instance, XL147 or GDC-0941 are inhibitors for the P13kinase mutation that are in clinical trials at present.  In addition, someone’s cancer could harbor a mutation (such as ALK) that is not known to be associated with ovarian cancer or has not yet been studied in ovarian cancer – these patients could be matched with a drug that inhibits that protein too. As new drugs get developed, this information would be used to match future drugs with patients and their cancers.”

The researchers hope that OncoMap will become a clinical test for all cancer patients at the Dana-Farber Cancer Institute before long, so that the genetic information obtained can be used to choose the best treatment for them.

Dr. Matulonis said:

“At present, only a few targeted therapies are being used for newly diagnosed ovarian cancer and most are being used to treat recurrent ovarian cancer, but this will change eventually. I have already referred several of our patients who are either newly diagnosed or have recurrent cancer and who have mutations (one with KRAS and one with PIK3CA) to our phase I program for drugs studies specific to these mutations.  For ovarian cancer, understanding mutational analysis is one piece of the genetic puzzle. Our group will also start looking for chromosomal and gene amplifications and deletions in patients’ tumors, which we know are important for ovarian cancer.”

Matulonis believes that OncoMap and other similar analytical tools will become mainstream practice in all cancer clinics before long. Tools for detecting genes with the incorrect numbers of copies or abnormal expression will also help doctors to choose the best treatment for individual patients.”

Source: Researchers map the way to personalised treatment for ovarian cancer, Abstract no: 35. Oral presentation in plenary session 2.  22nd EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics, Berlin, Germany, November 16- 19, 2010.

References:

[1] EORTC [European Organisation for Research and Treatment of Cancer, NCI [National Cancer Institute], AACR [American Association for Cancer Research].

[2] The study was funded by the Madeline Franchi Ovarian Cancer Research Fund, twoAM Fund and the Sally Cooke Ovarian Cancer Research Fund.

Related Information:

Expression of Proteins Linked to Poor Outcome in Women with Ovarian Cancer

Scientists have established the presence of certain proteins in ovarian cancer tissues and have linked these proteins to poor survival rates in women with advanced stages of the disease.

Christina M. Annunziata, M.D., Ph.D., Assistant Clinical Investigator, Medical Oncology Branch & Affiliates, Molecular Signaling Section, National Cancer Institute

NF-kB Signaling Pathway

Scientists have established the presence of certain proteins in ovarian cancer tissues and have linked these proteins to poor survival rates in women with advanced stages of the disease. The study, led by scientists at the National Cancer Institute (NCI), part of the National Institutes of Health, appears in Cancer online, April 19, 2010.

The proteins in question belong to the nuclear factor kappa Beta (NF-kB) family. NF-kB controls many processes within the cell including cell survival and proliferation, inflammation, immune responses, and cellular responses to stress.

“This study sheds light on the distinctive genetic features of the NF-kB pathway and may provide targets for the development of novel therapies for ovarian cancer,” said lead investigator, Christina M. Annunziata, M.D., Ph.D., associate clinical investigator, Medical Oncology Branch.

Abnormalities in NF-kB signaling have been found in several types of cancer, including ovarian cancer, but the mechanism and importance of such alterations in ovarian cancer was not defined. To address these knowledge gaps, the research team investigated the expression of NF-kB-related proteins in the cells of tumor tissue obtained at surgery from 33 previously untreated women who were newly diagnosed with advanced epithelial ovarian cancer. The patients had similar stage (all late stage), grade, and type of disease. All patients were treated with a three-drug regimen of standard chemotherapy agents in an NCI clinical trial that was conducted at the NIH Clinical Research Center.

To assess NF-kB family members and associated proteins in ovarian tumor cells, the scientists used immunohistochemistry, a method that uses antibodies — a type of protein that the body’s immune system produces when it detects harmful substances — to identify specific molecules in tissue specimens. Subsequently, they looked for associations between the percentage of tumor cells in individual proteins and patient outcomes.

“This study sheds light on the distinctive genetic features of the NF-kB pathway and may provide targets for the development of novel therapies for ovarian cancer,” said lead investigator, Christina M. Annunziata, M.D., Ph.D.

The data revealed that the presence of one NF-kB family member—p50—in more than one-quarter of the cells was associated with poor survival. Low-frequency or nonexpression of a target gene, matrix metallopeptidase 9 (MMP9), was also associated with poor prognosis. Further, the team identified two NF-kB family members—p65 and RelB—and a protein called IKKa that plays a role in promoting inflammation, that were frequently expressed in the same cells, providing more evidence that NF-kB is active in some ovarian cancers. It is possible that the NF-kB activity in these cancers could increase their growth and/or resistance to treatment.

“This work continues to define and characterize the biological relevance of NF-kB activity in ovarian cancer by translating research findings with ovarian cancer cells in the laboratory to ovarian cancer in women at the time of initial diagnosis,” said Annunziata.

About the National Cancer Institute

NCI leads the National Cancer Program and the NIH effort to dramatically reduce the burden of cancer and improve the lives of cancer patients and their families, through research into prevention and cancer biology, the development of new interventions, and the training and mentoring of new researchers. For more information about cancer, please visit the NCI Web site at http://www.cancer.gov or call NCI’s Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).

About the National Institutes of Health

The National Institutes of Health (NIH) — The Nation’s Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

Comment

If NF-kB activity is ultimately determined by Dr. Annunciata et. al. to be biologically significant to ovarian cancer cell growth and/or treatment resistance, there are NF-kB inhibitor drugs (e.g., bortezomib (Velcade) or denosumab (Prolia)) in existence that theoretically could be tested in ovarian cancer clinical trials. In addition genistein, a soy isoflavone, and BAY11-7082, a preclinical compound, could be tested through preclinical/clinical testing as potential NF-kB inhibitors.  See Miller SC et. al. study below for a complete list of known NF-kB pathway inhibiting drugs and compounds.

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GOG Says Continuation of Pivotal OPAXIO Maintenance Therapy Trial (GOG-212) Remains High Priority

Gynecologic Oncology Group (GOG) Notifies CTI That Continuation of GOG-212 Pivotal Trial of OPAXIO Maintenance Therapy in Front Line Ovarian Cancer Remains High Priority.  GOG-218 Bevacizumab Results Do Not Influence Importance of GOG-212

Cell Therapeutics, Inc. (“CTI”) announced today that the company received a statement on March 1, 2010 from the Gynecologic Oncology Group (GOG) leadership that the phase III GOG-212 clinical trial of CTI’s OPAXIO™ (formerly known as Xyotax or CT-2103) used as maintenance therapy for ovarian cancer remains a high priority and enrollment will continue. The GOG made the statement to clarify that the recent results of the GOG-218 clinical trial bevacizumab in maintenance therapy for ovarian cancer has not influenced the importance of completing the GOG-212 clinical trial. The Gynecologic Oncology Group (GOG) is one of the National Cancer Institute’s (NCI) funded cooperative cancer research groups. The GOG is a multidisciplinary cooperative clinical trial research group focused on the study of gynecologic malignancies. The GOG is conducting phase III trials in ovarian cancer and other gynecologic cancers and has established standard treatments for these diseases in the U.S.

GOG leadership noted the following:

GOG-218 and GOG-212 differ in the type of patients under study. It is important to note that some of the patients who completed the initial 6 cycles of chemotherapy in GOG-218 had clinical evidence of persistent tumor and were randomized to either placebo (no treatment) or bevacizumab [Avastin®]. Thus a subset of GOG-218 patients received no therapy, despite the presence of persistent tumor. This is not the typical setting of using maintenance or consolidation therapy and it is not the setting for patients enrolled in GOG-212. In GOG-212, only patients who have achieved a complete clinical response are considered candidates for enrollment in the trial.

Reliance upon the data from GOG-218 to establish the “standard of care” must take into consideration the actual treatment effect (i.e., duration of benefit), the cost of the treatment, and the associated toxicity… [in GOG-212] the toxicity of the intervention may have less associated mortality and the incremental cost-effectiveness ratio may be more acceptable to patients and the health care economists. Thus the GOG has no intention to discontinue enrollment in GOG 212 as they feel that the study is addressing a different scientific question and the primary outcome study goal is survival, not progression free survival, an outcome of greater importance to both physicians and patients.

The Data Monitoring Committee is scheduled to conduct an interim analysis of overall survival when 130 events are recorded among patients in the no maintenance treatment arm. The statistical analysis plan utilizes pre-specified boundaries for early stopping for success. Based on current enrollment and study duration, the interim analysis could be conducted as early as 2011. If successful, CTI could utilize those results to form the basis of its New Drug Application for OPAXIO.

About Cell Therapeutics, Inc.

Headquartered in Seattle, CTI is a biopharmaceutical company committed to developing an integrated portfolio of oncology products aimed at making cancer more treatable. For additional information, please visit http://www.celltherapeutics.com/.

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Genentech Announces Positive Results of Avastin Phase III Study in Women with Advanced Ovarian Cancer

Genentech announces positive results of Avastin Phase III study (GOG 218) in women with advanced ovarian cancer. The study showed that women who continued maintenance use of Avastin alone, after receiving Avastin in combination with chemotherapy, lived longer without the disease worsening compared to those who received chemotherapy alone. This is the first Phase III study of an anti-angiogenic therapy in advanced ovarian cancer to meet its primary endpoint.

Tumor angiogenesis is the proliferation of a network of blood vessels that penetrates into cancerous growths, supplying nutrients and oxygen and removing waste products. Tumor angiogenesis actually starts with cancerous tumor cells releasing molecules that send signals to surrounding normal host tissue. This signaling activates certain genes in the host tissue that, in turn, make proteins to encourage growth of new blood vessels. Photo credit: NCI

Genentech, Inc., a wholly owned member of the Roche Group , today announced that a Phase III study showed the combination of Avastin® (bevacizumab) and chemotherapy followed by maintenance use of Avastin alone increased the time women with previously untreated advanced ovarian cancer lived without the disease worsening (progression-free survival or PFS), compared to chemotherapy alone. A preliminary assessment of safety noted adverse events previously observed in pivotal trials of Avastin. Data from the study will be submitted for presentation at the American Society of Clinical Oncology (ASCO) annual meeting, June 4 – 8, 2010.

In the three-arm study, known as Gynecologic Oncology Group (GOG) 0218, women with newly diagnosed advanced ovarian cancer who already had surgery to remove as much of the tumor as possible were randomized to receive one of the following:

  • Arm 1: Placebo in combination with carboplatin and paclitaxel chemotherapy followed by placebo alone, for a total of up to 15 months of therapy
  • Arm 2: Avastin in combination with carboplatin and paclitaxel chemotherapy followed by placebo alone, for a total of up to 15 months of therapy
  • Arm 3: Avastin in combination with carboplatin and paclitaxel chemotherapy followed by the maintenance use of Avastin alone, for a total of up to 15 months of therapy.

The study showed that women who continued maintenance use of Avastin alone, after receiving Avastin in combination with chemotherapy (Arm 3), lived longer without the disease worsening compared to those who received chemotherapy alone. Women who received Avastin in combination with chemotherapy, but did not continue maintenance use of Avastin alone (Arm 2), did not live longer without the disease worsening compared to chemotherapy alone.

“Additional medicines are urgently needed for women with newly diagnosed advanced ovarian cancer, as most women’s cancer will worsen after their initial treatment,” said Hal Barron, M.D., F.A.C.C., Executive Vice President, Global Development and Chief Medical Officer. “We are encouraged by the positive findings of this study, which highlight the importance of continuing maintenance Avastin after combining Avastin with chemotherapy in this setting. We will discuss these results with the U.S. Food and Drug Administration.”

Robert Allen Burger, MD, FACOG, FACS, Fox Chase Cancer Center, Philadelphia, Pennsylvania

“This is good news for women with ovarian, primary peritoneal or fallopian tube cancers,” said GOG 0218 study chair Robert Burger, M.D., Fox-Chase Cancer Center in Philadelphia. “This study showed that after initial surgery, the combination of Avastin and chemotherapy followed by extended treatment with Avastin improves progression-free survival in women with newly diagnosed advanced tumors.”

The trial is sponsored by the National Cancer Institute (NCI) under a Cooperative Research and Development Agreement between the NCI and Genentech, and is being conducted by a network of researchers led by the GOG.

Avastin is being studied worldwide in more than 450 clinical trials for multiple types of cancer, including approximately 25 ongoing clinical trials in the United States for women with various stages of ovarian cancer.

About Ovarian Cancer

According to the American Cancer Society, ovarian cancer is the fifth leading cause of cancer death among American women. In 2009 an estimated 21,500 women were diagnosed with ovarian cancer and approximately 14,500 died from the disease in the U.S. The disease causes more deaths than any other gynecologic cancer, and the American Cancer Society estimates that nearly 70 percent of women with advanced disease will die from it within five years.

Ovarian cancer is associated with high levels of vascular endothelial growth factor (VEGF), a protein associated with tumor growth and spread. Studies have shown a correlation between a high level of VEGF and a poorer prognosis in women with ovarian cancer. Currently, treatment options for women with this disease are limited to surgery and chemotherapy.

About the GOG 0218 Study

GOG 0218 is an international, multicenter, randomized, double-blind, placebo-controlled Phase III study in 1,873 women with previously untreated advanced epithelial ovarian, primary peritoneal or fallopian tube carcinoma. The study evaluates Avastin (5 cycles) in combination with carboplatin and paclitaxel chemotherapy (6 cycles) compared to carboplatin and paclitaxel chemotherapy alone (6 cycles). The trial is also designed to assess the maintenance use of Avastin alone following the initial combined regimen of Avastin and chemotherapy (for a total of up to 15 months of therapy), compared to carboplatin and paclitaxel chemotherapy alone (6 cycles).

The primary endpoint of the study is PFS as assessed by trial investigators. Secondary and exploratory endpoints of the study include overall survival, PFS by independent review, objective response rate, safety, quality of life measures and analysis of patient tumor and blood samples.

Detailed safety assessments are ongoing. A preliminary assessment of safety performed by the GOG identified Avastin-related serious adverse events noted in previous pivotal studies, including fatal neutropenic infection and gastrointestinal perforation. The full study results, including safety information, will be presented at a future medical meeting.

About Avastin

Avastin is a solution for intravenous infusion and is a biologic antibody designed to specifically bind to a protein called VEGF. VEGF plays an important role throughout the lifecycle of the tumor to develop and maintain blood vessels, a process known as angiogenesis. Avastin interferes with the tumor blood supply by directly binding to the VEGF protein to prevent interactions with receptors on blood vessel cells. Avastin does not bind to receptors on normal or cancer cells. The tumor blood supply is thought to be critical to a tumor’s ability to grow and spread in the body (metastasize). For more information about angiogenesis, visit http://www.gene.com.

Boxed WARNINGS and Additional Important Safety Information

People treated with Avastin may experience side effects. In clinical trials, some people treated with Avastin experienced serious and sometimes fatal side effects, including:

Gastrointestinal (GI) perforation: Treatment with Avastin can result in the development of a potentially serious side effect called GI perforation, which is the development of a hole in the stomach, small intestine or large intestine. In clinical trials, this side effect occurred in more people who received Avastin than in the comparison group (0.3 percent to 2.4 percent). In some cases, GI perforation resulted in fatality.

Surgery and wound healing problems: Treatment with Avastin can lead to slow or incomplete wound healing (for example, when a surgical incision has trouble healing or staying closed). In some cases, this event resulted in fatality. Surgery and wound healing problems occurred more often in people who received Avastin than in the comparison group. Avastin therapy should not be started for at least 28 days after surgery and until the surgical wound is fully healed. The length of time between stopping Avastin and having voluntary surgery without the risk of having surgery and wound healing problems following surgery has not been determined.

Severe bleeding: Treatment with Avastin can result in serious bleeding, including coughing up blood, bleeding in the stomach, vomiting of blood, bleeding in the brain, nosebleeds and vaginal bleeding. These events occurred up to five times more often in people who received Avastin. Across cancer types, 1.2 percent to 4.6 percent of people who received Avastin experienced severe to fatal bleeding. People who have recently coughed up blood (greater than or equal to a half teaspoon of red blood) or have serious bleeding should not receive Avastin.

In clinical trials for different cancer types, there were additional serious and sometimes fatal side effects that occurred in more people who received Avastin than in those in the comparison group. The formation of an abnormal passage from parts of the body to another part (non-GI fistula formation) was seen in 0.3 percent or less of people. Severe to life-threatening stroke or heart problems were seen in 2.4 percent of people. Too much protein in the urine, which led to kidney problems, was seen in less than 1 percent of people. Additional serious side effects that occurred in more people who received Avastin than those in the comparison group included severe to life-threatening high blood pressure, which was seen in 5 percent to 18 percent of people, and nervous system and vision disturbances (reversible posterior leukoencephalopathy syndrome), which was seen in less than 0.1 percent of people. Infusion reactions with the first dose of Avastin were uncommon and occurred in less than 3 percent of people and severe reactions occurred in 0.2 percent of people.

Common side effects that occurred in more than 10 percent of people who received Avastin for different cancer types, and at least twice the rate of the comparison group, were nosebleeds, headache, high blood pressure, inflammation of the nose, too much protein in the urine, taste change, dry skin, rectal bleeding, tear production disorder, back pain and inflammation of the skin (exfoliative dermatitis). Across all trials, treatment with Avastin was permanently stopped in 8.4 percent to 21 percent of people because of side effects.

Avastin may impair fertility. Patients who are pregnant or thinking of becoming pregnant should talk with their doctor about the potential risk of loss of the pregnancy or the potential risk of Avastin to the fetus during and following Avastin therapy, and the need to continue an effective birth control method for at least six months following the last dose of Avastin.

For full Prescribing Information and Boxed WARNINGS on Avastin please visit http://www.avastin.com.

About Genentech

Founded more than 30 years ago, Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes medicines to treat patients with serious or life-threatening medical conditions. The company, a wholly owned member of the Roche Group, has headquarters in South San Francisco, California. For additional information about the company, please visit http://www.gene.com.

About The Gynecologic Oncology Group (GOG)

The Gynecologic Oncology Group is a non-profit organization of more than 300 member institutions with the purpose of promoting excellence in the quality and integrity of clinical and basic scientific research in the field of Gynecologic malignancies. The Group is committed to maintaining the highest standards in the clinical trial development, execution, analysis and distribution of results. Continuous evaluation of our processes is utilized in order to constantly improve the quality of patient care.

GOG receives support from the National Cancer Institute (NCI) of the National Institutes for Health (NIH).

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