Phenoxodiol Used In Combination With Platinum or Taxane-Based Chemotherapy Is Active In Platinum & Taxane-Resistant Ovarian Cancer

Phase II clinical study results suggests phenoxodiol is active in platinum and taxane drug-resistant ovarian cancer patients when administered intravenously in combination with platinum or taxane-based chemotherapy

Marshall Edwards, Inc., an oncology company focused on the clinical development of novel therapeutics targeting cancer metabolism, recently announced the publication of results from a phase II clinical trial of intravenous phenoxodiol in combination with cisplatin or paclitaxel in women with platinumrefractory/resistant ovarian cancer. The publication is now available on the International Journal of Gynecological Cancer website, and the print edition will appear the May issue of the journal.

The study, conducted at Yale-New Haven Hospital, showed that the combination of intravenous phenoxodiol, a novel NADH oxidase inhibitor, with cisplatin (a platinum-based chemotherapy) or paclitaxel (a taxane-based chemotherapy), was well tolerated.

Robert D. Mass, M.D., Acting Chief Medical Officer, Marshall Edwards.

In the study, 32 patients were randomized to one of two treatment arms according to their previous treatment responses: (1) platinum refractory/resistant patients received weekly cisplatin (40 mg/m intravenous), combined with weekly phenoxodiol (3 mg/kg); and (2) taxane refractory/resistant patients received weekly paclitaxel (80 mg/m intravenous), combined with weekly phenoxodiol (3 mg/kg). The study patients continued on treatment until complete response, disease progression, unacceptable toxicity, or voluntary withdrawal.

In the cisplatin study arm, there were 3 partial responses, 9 patients (56%) achieved stable disease, 4 patients (25%) progressed, and the overall best response rate was 19%. In the paclitaxel study arm, there was one complete response and 2 partial responses, 8 patients (53%) achieved stable disease, 4 patients (27%) progressed, and the overall best response rate was 20%. Response rate in this study was defined as the percentage of patients whose tumor demonstrated a radiologically confirmed reduction or disappearance after treatment.

There were no treatment-related deaths in the study, and there was only one treatment-related hospitalization and two grade 4 (i.e., life-threatening or disabling) adverse events.

Based upon the foregoing results, the researchers concluded that the combination of intravenous phenoxodiol with cisplatin or paclitaxel was well tolerated.  Moreover, the researchers stated that the cisplatin-phenoxodiol combination was particularly active and warrants further study in patients with platinum-resistant ovarian cancer.

“These results suggest that the combination of intravenous phenoxodiol with cisplatin has a good safety profile and may be capable of reversing resistance to platinum-based chemotherapy,” said lead author Michael G. Kelly, M.D., a gynecologic oncologist at Tufts Medical Center and former fellow at Yale University School of Medicine.” This study provides early clinical proof-of-concept for the combination of NADH oxidase inhibitors with standard-of-care chemotherapy and lays the groundwork for the development of more potent next-generation compounds.”

To date, phenoxodiol, an investigational drug, has been introduced into more than 400 patients in multiple clinical trials via oral or intravenous routes and has been well tolerated. Marshall Edwards has identified a next-generation compound called “NV-143,” which has demonstrated significantly more activity than phenoxodiol against a broad range of tumor cell lines. In addition to being more active as a single agent, NV-143 appears to be superior in its ability to synergize with platinum-based chemotherapy in pre-clinical studies. As a result, Marshall Edwards plans to initiate a phase I clinical trial of intravenous NV-143 later this year, followed immediately thereafter by randomized phase II trials in combination with chemotherapy.

“These published results combined with data from previous studies reinforce our conclusion that intravenous administration is the optimal route of delivery for this class of drugs and give us added confidence moving forward as we develop our next-generation compound NV-143 for the clinic,” said Robert D. Mass, M.D., Acting Chief Medical Officer of Marshall Edwards.

About Marshall Edwards

Marshall Edwards, Inc. is a San Diego-based oncology company focused on the clinical development of novel anti-cancer therapeutics. The Company’s lead programs focus on two families of small molecules that result in the inhibition of tumor cell metabolism. The first and most advanced is a NADH oxidase inhibitor program that includes lead drug candidate NV-143. The second is a mitochondrial inhibitor program that includes NV-128 and its next-generation candidate NV-344. Both programs are expected to advance into the clinic in 2011. For more information, visit www.marshalledwardsinc.com.

About Novogen Limited

Novogen Limited is an Australian biotechnology company based in Sydney, Australia. Novogen has a consumer healthcare business, and conducts research and development on oncology therapeutics through its 71.3% owned subsidiary, Marshall Edwards, Inc.

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Largest Study Matching Genomes To Potential Anticancer Treatments Releases Initial Results

The largest study to correlate genetics with response to anticancer drugs released its first results on July 15. The researchers behind the study, based at Massachusetts General Hospital Cancer Center and the Wellcome Trust Sanger Institute, describe in this initial dataset the responses of 350 cancer samples (including ovarian cancer) to 18 anticancer therapeutics.

U.K.–U.S. Collaboration Builds a Database For “Personalized” Cancer Treatment

The Genomics of Drug Sensitivity in Cancer project released its first results on July 15th. Researchers released a first dataset from a study that will expose 1,000 cancer cell lines (including ovarian) to 400 anticancer treatments.

The largest study to correlate genetics with response to anticancer drugs released its first results on July 15. The researchers behind the study, based at Massachusetts General Hospital Cancer Center and the Wellcome Trust Sanger Institute, describe in this initial dataset the responses of 350 cancer samples (including ovarian cancer) to 18 anticancer therapeutics.

These first results, made freely available on the Genomics of Drug Sensitivity in Cancer website, will help cancer researchers around the world to obtain a better understanding of cancer genetics and could help to improve treatment regimens.

Dr. Andy Futreal, co-leader of the Cancer Genome Project at the Wellcome Trust Sanger Institute, said:

Today is our first glimpse of this complex interface, where genomes meet cancer medicine. We will, over the course of this work, add to this picture, identifying genetic changes that can inform clinical decisions, with the hope of improving treatment.  By producing a carefully curated set of data to serve the cancer research community, we hope to produce a database for improving patient response during cancer treatment.

How a patient responds to anticancer treatment is determined in large part by the combination of gene mutations in her or his cancer cells. The better this relationship is understood, the better treatment can be targeted to the particular tumor.

The aim of the five-year, international drug-sensitivity study is to find the best combinations of treatments for a wide range of cancer types: roughly 1000 cancer cell lines will be exposed to 400 anticancer treatments, alone or in combination, to determine the most effective drug or combination of drugs in the lab.

The therapies include known anticancer drugs as well as others in preclinical development.

To make the study as comprehensive as possible, the researchers have selected 1000 genetically characterized cell lines that include common cancers such as breast, colorectal and lung. Each cell line has been genetically fingerprinted and this data will also be publicly available on the website. Importantly, the researchers will take promising leads from the cancer samples in the lab to be verified in clinical specimens: the findings will be used to design clinical studies in which treatment will be selected based on a patient’s cancer mutation spectrum.

The new data released today draws on large-scale analyses of cancer genomes to identify genomic markers of sensitivity to anticancer drugs.

The first data release confirms several genes that predict therapeutic response in different cancer types. These include sensitivity of melanoma, a deadly form of skin cancer, with activating mutations in the gene BRAF to molecular therapeutics targeting this protein, a therapeutic strategy that is currently being exploited in the clinical setting. These first results provide a striking example of the power of this approach to identify genetic factors that determine drug response.

Dr. Ultan McDermott, Faculty Investigator at the Wellcome Trust Sanger Institute, said:

It is very encouraging that we are able to clearly identify drug–gene interactions that are known to have clinical impact at an early stage in the study. It suggests that we will discover many novel interactions even before we have the full complement of cancer cell lines and drugs screened. We have already studied more gene mutation-drug interactions than any previous work but, more importantly, we are putting in place a mechanism to ensure rapid dissemination of our results to enable worldwide collaborative research. By ensuring that all the drug sensitivity data and correlative analysis is freely available in an easy-to-use website, we hope to enable and support the important work of the wider community of cancer researchers.

Further results from this study should, over its five-year term, identify interactions between mutations and drug sensitivities most likely to translate into benefit for patients: at the moment we do not have sufficient understanding of the complexity of cancer drug response to optimize treatment based on a person’s genome.

Professor Daniel Haber, Director of the Cancer Center at Massachusetts General Hospital and Harvard Medical School, said:

We need better information linking tumor genotypes to drug sensitivities across the broad spectrum of cancer heterogeneity, and then we need to be in position to apply that research foundation to improve patient care.  The effectiveness of novel targeted cancer agents could be substantially improved by directing treatment towards those patients that genetic study suggests are most likely to benefit, thus “personalizing” cancer treatment.

The comprehensive results include correlating drug sensitivity with measurements of mutations in key cancer genes, structural changes in the cancer cells (copy number information) and differences in gene activity, making this the largest project of its type and a unique resource for cancer researchers around the world.

Professor Michael Stratton, co-leader of the Cancer Genome Project and Director of the Wellcome Trust Sanger Institute, said:

“This is one of the Sanger Institute’s first large-scale explorations into the therapeutics of human disease.  I am delighted to see the early results from our partnership with the team at Massachusetts General Hospital. Collaboration is essential in cancer research: this important project is part of wider efforts to bring international expertise to bear on cancer.”

Ovarian Cancer Sample Gene Mutation Prevalence

As part of the Cancer Genome Project, researchers identified gene mutations found in 20 ovarian cancer cell lines and the associated prevalence of such mutations within the sample population tested. For purposes of this project, a mutation — referred to by researchers as a “genetic event” in the project analyses description — is defined as (i) a coding sequence variant in a cancer gene, or (ii) a gene copy number equal to zero (i.e., a gene deletion) or greater than or equal to 8 (i.e., gene amplification).  The ovarian cancer sample analysis thus far, indicates the presence of mutations in twelve genes. The genes that are mutated and the accompanying mutation prevalence percentage are as follows:  APC (5%), CDKN2A (24%), CTNNB1 (5%), ERBB2/HER-2 (5%), KRAS (10% ), MAP2K4 (5%), MSH2 (5%), NRAS (10%), PIK3CA (10%), PTEN (14%), STK11 (5%), and TP53 (62%). Accordingly, as of date, the top five ovarian cancer gene mutations occurred in TP53, CDKN2A, CDKN2a(p14)(see below), PTEN, and KRAS.

Click here to view the Ovary Tissue Overview.  Click here to download a Microsoft Excel spreadsheet listing the mutations in 52 cancer genes across tissue types. Based upon the Ovary Tissue Overview chart, the Microsoft Excel Chart has not been updated to include the following additional ovarian cancer sample mutations and associated prevalence percentages: CDKN2a(p14)(24%), FAM123B (5%), FBXW7 (5%), MLH1 (10%), MSH6 (5%).

18 AntiCancer Therapies Tested; Next 9 Therapies To Be Tested Identified

As presented in the initial study results, 18 drugs/preclinical compounds were tested against various cancer cell lines, including ovarian. The list of drugs/preclinical compounds that were tested for sensitivity are as follows:  imatinib (brand name: Gleevec),  AZ628 (C-Raf inhibitor)MG132 (proteasome inhibitor), TAE684 (ALK inhibitor), MK-0457 (Aurora kinase inhibitor)sorafenib (C-Raf kinase & angiogenesis inhibitor) (brand name: Nexavar), Go 6976 (protein kinase C (PKC) inhibitor), paclitaxel (brand name: Taxol), rapamycin (mTOR inhibitor)(brand name: Rapamune), erlotinib (EGFR inhibitor)(brand name: Tarceva), HKI-272 (a/k/a neratinib) (HER-2 inhibitor), Geldanamycin (Heat Shock Protein 90 inhibitor), cyclopamine (Hedgehog pathway inhibitor), AZD-0530 (Src and Abl inhibitor), sunitinib (angiogenesis & c-kit inhibitor)(brand name:  Sutent), PHA665752 (c-Met inhibitor), PF-2341066 (c-Met inhibitor), and PD173074 (FGFR1 & angiogenesis inhibitor).

Click here to view the project drug/preclinical compound sensitivity data chart.

The additional drugs/compounds that will be screened by researchers in the near future are metformin (insulin)(brand name:  Glucophage), AICAR (AMP inhibitor), docetaxel (platinum drug)(brand name: Taxotere), cisplatin (platinum drug)(brand name: Platinol), gefitinib (EGFR inhibitor)(brand name:  Iressa), BIBW 2992 (EGFR/HER-2 inhibitor)(brand name:  Tovok), PLX4720 (B-Raf [V600E] inhibitor), axitinib (angiogenesis inhibitor)(a/k/a AG-013736), and CI-1040 (PD184352)(MEK inhibitor).

Ovarian cancer cells dividing. (Source: ecancermedia)

Ovarian Cancer Therapy Sensitivity

Targeted molecular therapies that disrupt specific intracellular signaling pathways are increasingly used for the treatment of cancer. The rational for this approach is based on our ever increasing understanding of the genes that are causally implicated in cancer and the clinical observation that the genetic features of a cancer can be predictive of a patient’s response to targeted therapies. As noted above, the goal of the Cancer Genome Project is to discover new cancer biomarkers that define subsets of drug-sensitive patients. Towards this aim, the researchers are (i) screening a wide range of anti-cancer therapeutics against a large number of genetically characterized human cancer cell lines (including ovarian), and (ii) correlating drug sensitivity with extensive genetic data. This information can be used to determine the optimal clinical application of cancer drugs as well as the design of clinical trials involving investigational compounds being developed for the clinic.

When the researchers tested the 18 anticancer therapies against the 20 ovarian cancer cell lines, they determined that the samples were sensitive to many of the drugs/compounds. The initial results of this testing indicate that there are at least six ovarian cancer gene mutations that were sensitive to eight of the anticancer therapies, with such results rising to the level of statistical significance.  We should note that although most (but not all) of the ovarian cancer gene mutations were sensitive to several anticancer therapies, we listed below only those which were sensitive enough to be assigned a green (i.e., sensitive) heatmap code by the researchers.

Click here to download a Microsoft Excel spreadsheet showing the effect of each of the 51 genes on the 18 drugs tested. Statistically significant effects are highlighted in bold and the corresponding p values for each gene/drug interaction are displayed in an adjacent table.  A heatmap overlay for the effect of the gene on drug sensitivity was created, with the color red indicating drug resistance and the color green indicating drug sensitivity.

The mutated genes present within the 20 ovarian cancer cell line sample that were sensitive to anticancer therapies are listed below.  Again, only statistically significant sensitivities are provided.

  • CDKN2A gene mutation was sensitive to TAE684, MK-0457, paclitaxel, and PHA665752.
  • CTNNB1 gene mutation was sensitive to MK-0457.
  • ERBB2/HER-2 gene mutation was sensitive to HKI-272.
  • KRAS gene mutation was sensitive to AZ628.
  • MSH2 gene mutation was sensitive to AZD0530.
  • NRAS gene mutation was sensitive to AZ628.

We will provide you with future updates regarding additional ovarian cancer gene mutation findings, and new anticancer therapies tested, pursuant to the ongoing Cancer Genome Project.

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About The Genomics of Drug Sensitivity In Cancer Project

The Genomics of Drug Sensitivity In Cancer Project was launched in December 2008 with funding from a five-year Wellcome Trust strategic award. The U.K.–U.S. collaboration harnesses the experience in experimental molecular therapeutics at Massachusetts General Hospital Cancer Center and the expertise in large scale genomics, sequencing and informatics at the Wellcome Trust Sanger Institute. The scientists will use their skills in high-throughput research to test the sensitivity of 1000 cancer cell samples to hundreds of known and novel molecular anticancer treatments and correlate these responses to the genes known to be driving the cancers. The study makes use of a very large collection of genetically defined cancer cell lines to identify genetic events that predict response to cancer drugs. The results will give a catalogue of the most promising treatments or combinations of treatments for each of the cancer types based on the specific genetic alterations in these cancers. This information will then be used to empower more informative clinical trials thus aiding the use of targeted agents in the clinic and ultimately improvements in patient care.

Project leadership includes Professor Daniel Haber and Dr. Cyril Benes at Massachusetts General Hospital Cancer Center and Professor Mike Stratton and Drs. Andy Futreal and Ultan McDermott at the Wellcome Trust Sanger Institute.

About Massachusetts General Hospital

Massachusetts General Hospital (MGH), 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.

About The Wellcome Trust Sanger Institute

The Wellcome Trust Sanger Institute, which receives the majority of its funding from the Wellcome Trust, was founded in 1992 as the focus for U.K. gene sequencing efforts. The Institute is responsible for the completion of the sequence of approximately one-third of the human genome as well as genomes of model organisms such as mouse and zebrafish, and more than 90 pathogen genomes. In October 2005, new funding was awarded by the Wellcome Trust to enable the Institute to build on its world-class scientific achievements and exploit the wealth of genome data now available to answer important questions about health and disease. These programs are built around a Faculty of more than 30 senior researchers. The Wellcome Trust Sanger Institute is based in Hinxton, Cambridge, U.K.

About The Wellcome Trust

The Wellcome Trust is a global charity dedicated to achieving extraordinary improvements in human and animal health. It supports the brightest minds in biomedical research and the medical humanities. The Trust’s breadth of support includes public engagement, education, and the application of research to improve health. It is independent of both political and commercial interests.

Required Cancer Genome Project Disclaimer:

The data above was obtained from the Wellcome Trust Sanger Institute Cancer Genome Project web site, http://www.sanger.ac.uk/genetics/CGP. The data is made available before scientific publication with the understanding that the Wellcom Trust Sanger Institute intends to publish the initial large-scale analysis of the dataset. This publication will include a summary detailing the curated data and its key features.  Any redistribution of the original data should carry this notice: Please ensure that you use the latest available version of the data as it is being continually updated.  If you have any questions regarding the sequence or mutation data or their use in publications, please contact cosmic@sanger.ac.uk so as to obtain any updated or additional data.  The Wellcome Trust Sanger Institute provides this data in good faith, but makes no warranty, express or implied, nor assumes any legal liability or responsibility for any purpose for which the data are used.

Researchers Identify “Missing Link” Underlying DNA Repair & Platinum Drug Resistance

Researchers have discovered an enzyme crucial to a type of DNA repair that also causes resistance to a class of cancer drugs most commonly used against ovarian cancer.

Scientists from The University of Texas MD Anderson Cancer Center and the Life Sciences Institute of Zhejiang University in China report the discovery of the enzyme and its role in repairing DNA damage called “cross-linking” in the Science Express advance online publication of Science.

Junjie Chen, Ph.D., Professor and Chair, Department of Experimental Radiation Oncology, University of Texas M.D. Anderson Cancer Center

“This pathway that repairs cross-linking damage is a common factor in a variety of cancers, including breast cancer and especially in ovarian cancer. If the pathway is active, it undoes the therapeutic effect of cisplatin and similar therapies,” said co-corresponding author Junjie Chen, Ph.D., professor and chair of MD Anderson’s Department of Experimental Radiation Oncology.

The platinum-based chemotherapies such as cisplatin, carboplatin and oxaliplatin work by causing DNA cross-linking in cancer cells, which blocks their ability to divide and leads to cell death. Cross-linking occurs when one of the two strands of DNA in a cell branches out and links to the other strand.

Cisplatin and similar drugs are often initially effective against ovarian cancer, Chen said, but over time the disease becomes resistant and progresses.

Scientists have known that the protein complex known as FANCIFANCD2 responds to DNA damage and repairs cross-linking, but the details of how the complex works have been unknown. “The breakthrough in this research is that we finally found an enzyme involved in the repair process,” Chen said.

The enzyme, which they named FAN1, appears to be a nuclease, which is capable of slicing through strands of DNA.

In a series of experiments, Chen and colleagues demonstrated how the protein complex summons FAN1, connects with the enzyme and moves it to the site of DNA cross-linking. They also showed that FAN1 cleaves branched DNA but leaves the normal, separate double-stranded DNA alone. Mutant versions of FAN1 were unable to slice branched DNA.

Like a lock and key

The researchers also demonstrated that FAN1 cannot get at DNA damage without being taken there by the FANCI-FANCD2 protein complex, which detects and moves to the damaged site. The complex recruits the FAN1 enzyme by acquiring a single ubiquitin molecule. FAN1 connects with the complex by binding to the ubiquitin site.

“It’s like a lock and key system, once they fit, FAN1 is recruited,” Chen said.

Analyzing the activity of this repair pathway could guide treatment for cancer patients, Chen said, with the platinum-based therapies used when the cross-linking repair mechanism is less active.

Scientists had shown previously that DNA repair was much less efficient when FANCI and FANCD2 lack the single ubiquitin. DNA response and damage-repair proteins can be recruited to damage sites by the proteins’ ubiquitin-binding domains. The team first identified a protein that had both a ubiquitin-binding domain and a known nuclease domain. When they treated cells with mitomycin C, which promotes DNA cross-linking, that protein, then known as KIAA1018, gathered at damage sites. This led them to the functional experiments that established its role in DNA repair.

They renamed the protein FAN1, short for Fanconi anemia-associated nuclease 1. The FANCI-FANCD2 complex is ubiquitinated by an Fanconi anemia (FA) core complex containing eight FA proteins. These genes and proteins were discovered during research of FA, a rare disease caused by mutations in 13 fanc genes that is characterized by congenital malformations, bone marrow failure, cancer and hypersensitivity to DNA cross-linking agents.

Chen said the FANCI-FANCD2 pathway also is associated with the BRCA1 and BRCA2 pathways, which are involved in homologous recombination repair. Scientists know that homologous recombination repair is also required for the repair of DNA cross-links, but the exact details remain to be resolved, Chen said. Mutations to BRCA1 and BRCA2 are known to raise a woman’s risk for ovarian and breast cancers and are found in about 5-10 percent of women with either disease.

Co-authors with Chen are co-first author Gargi Ghosal, Ph.D., and Jingsong Yuan, Ph.D., also of Experimental Radiation Oncology at MD Anderson; and co-corresponding author Jun Huang, Ph.D., co-first author Ting Liu, Ph.D., of the Life Sciences Institute of Zhejiang University in Hangzhou, China.

This research was funded by a grant from the U.S. National Institutes of Health and the Startup Fund at Zhejiang University.

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MIT Develops New Platinum Compound As Powerful As Cisplatin But Better Able To Destroy Tumor Cells

MIT chemists have developed a new platinum compound that is as powerful as the commonly used anticancer drug cisplatin but better able to destroy tumor cells.

A diagram of cisplatin which is a platinum chemotherapy drug.

Massachusetts Institute of Technology chemists have developed a new platinum compound that is as powerful as the commonly

Stephen J. Lippard Ph.D., Arthur Amos Noyes Professor of Chemistry, Massachusetts Institute of Technology

used anticancer drug cisplatin but better able to destroy tumor cells.

The new compound, mitaplatin, combines cisplatin with another compound, dichloroacetate (DCA), which can alter the properties of mitochondria selectively in cancer cells. Cancer cells switch their mitochondrial properties to change the way they metabolize glucose compared to normal cells, and DCA specifically targets the altered mitochondria, leaving normal cells intact.

“This differential effect conveys on mitaplatin the ability to kill cancer cells selectively in a co-culture with normal fibroblast cells, the latter being unaffected at the doses that we apply,” says Stephen Lippard, the Arthur Amos Noyes Professor of Chemistry.

How they did it: The chemists designed mitaplatin so that when it enters a cell, it releases cisplatin and two units of DCA by intracellular reduction. Therefore, mitaplatin can attack nuclear DNA with cisplatin and mitochondria with DCA. DCA promotes the release of cell-death-promoting factors from the mitochondria, enhancing the cancer cell-killing abilities of cisplatin.

Next steps: Lippard’s laboratory has shown that in rodents, mitaplatin can be tolerated at much higher doses than cisplatin, and they have begun studies in mice transplanted with human tissues. If those results are promising, the researchers plan more studies for further demonstration of mitaplatin’s ability in cancer therapy.

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Unusual Metals May Forge New Ovarian & Colon Cancer Drugs

Drugs made using unusual metals could form an effective treatment against colon and ovarian cancer, including cancerous cells that have developed immunity to other drugs, according to research at the University of Warwick and the University of Leeds.

Drugs made using unusual metals could form an effective treatment against colon and ovarian cancer, including cancerous cells that have developed immunity to other drugs, according to research at the University of Warwick and the University of Leeds.

Dr. Peter Sadler

Professor Peter Sadler of the University of Warwick. (Photo: University of Warwick)

The study, published in the Journal of Medicinal Chemistry, showed that a range of compounds containing the two transition metals Ruthenium and Osmium, which are found in the same part of the periodic table as precious metals like platinum and gold, cause significant cell death in ovarian and colon cancer cells.

The compounds were also effective against ovarian cancer cells which are resistant to the drug Cisplatin, the most successful transition metal drug, which contains the metal platinum.

Dr Patrick McGowan, one of the lead authors of the research from the School of Chemistry at the University of Leeds, explains: “Ruthenium and Osmium compounds are showing very high levels of activity against ovarian cancer, which is a significant step forward in the field of medicinal chemistry.

Sabine H. van Rijt, lead researcher in the laboratory of Professor Peter Sadler in the Department of Chemistry at the University of Warwick, said:  “Most interestingly, cancerous cells that have shown resistance to the most successful transition metal drug, Cisplatin, show a high death rate with these new compounds.”

Professor Sadler, at the University of Warwick, commented that he is “excited by the novel design features in these compounds which might enable activity to be switched on and off”.

Cisplatin was discovered in the 1970s and is one of the most effective cancer drugs on the market, with a 95% cure rate against testicular cancer.  Since the success of Cisplatin, chemists all over the world have been trying to discover whether other transition metal compounds can be used to treat cancer.

In this type of anti-cancer drug transition metal atoms bind to DNA molecules which trigger apoptosis, or programmed cell death, in the cancerous cells.

The study is a collaboration between the universities of Warwick and Leeds and was funded by the Engineering and Physical Sciences Research Council (EPSRC).

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2008 ASCO Annual Meeting Abtracts Highlight Several Drugs That Show Promise Against Drug Resistant Ovarian Cancer

There were several drugs highlighted in clinical trial abstracts presented at the 2008 American Society of Clinical Oncology (ASCO) Annual Meeting that demonstrated varying degrees of effectiveness against drug resistant (i.e., recurrence within 6 to 12 months after completion of first line treatment) and/or drug refractory (i.e., recurrence within 6 months after completion of first line treatment) ovarian cancer. By “effectiveness,” we mean generally that the drug or drug combination produced a complete response, partial response, and/or disease stabilization (and in a few cases, a significant drop in the CA-125 tumor marker) in ovarian cancer tumors. To better understand how to intrepret a medical study abstract, click here. The 2008 ASCO Annual Meeting was held in Chicago, Illinois on May 30 – June 3, 2008.

A list of the drugs/drug combinations is provided below. Any drug covered in depth through an earlier H*O*P*E*™ weblog post is noted. We also included 2008 ASCO Annual Meeting abstracts that provide “solid tumor” clinical trial results with respect to studies that enrolled patients with ovarian cancer tumors. When evaluating the potential enrollment in a clinical trial at various treatment points, an ovarian cancer survivor should evaluate trials dedicated to ovarian cancer patients in entirety, as well as general “solid tumor” trials that allow enrollment of ovarian cancer patients. Generally, a patient should give first priority to dedicated ovarian cancer trials and use the solid tumor trials as a “backup” to the ovarian cancer trials. All questions regarding the priority assigned to, or proper sequencing of, clinical trials should be discussed in detail with your doctor(s). Treatment priority and sequencing issues arise, for example, when enrollment in one clinical trial potentially disqualifies the patient for a subsequent second clinical trial based upon the protocol (i.e., inclusion/exclusion criteria) of the second trial. This example assumes that both clinical trials are currently enrolling patients when trial enrollment is being evaluated by you and your doctor.

Abbreviation Legend:

ABSTR=2008 American Society of Clinical Oncology Annual Meeting Abtract; ASCO=American Society of Clinical Oncology; CA-125=cancer antigen 125; CEA=Carcinoembryonic Antigen (Tumor Marker); CR=Complete Response; CT=Computed Tomography

CTC=Common Toxicity Criteria; DCE-MRI=Dynamic Contrast Enhanced Magnetic Resonance Imaging; DLT=Dose Limiting Toxicity; DP=Disease Progression; EOC=Epithelial Ovarian Cancer; G=Grade of Adverse Drug Effect;

GCIG=Gynecologic Cancer Intergroup; GOGGynecologic Oncology Group; MTD=Maximum Tolerable Dose; mg/m²=milligrams per metre squared; NCI=National Cancer Institute; OR=Objective Response; OS=Overall Survival;

PET=Positron Emission Tomography Scanning; PK=Pharmacokinetics; PO=Oral Administration; PR=Partial Response; PFS=Progression Free Survival; RECIST=Response Evaluation Criteria in Solid Tumors; RR=Response Rate; SD=Stable Disease

SNS-595 (Voreloxin®):

NOV-002 & Carboplatin (Paraplatin®):

  • NOV-002 plus carboplatin in platinum-resistant ovarian cancer (2008 ASCO Abstract #5593). Patients were heavily pretreated with 11/15 patients having received 3 prior [treatment] lines. Toxicity was mild-moderate with no G4 toxicity. There was no febrile neutropenia. The most common toxicities were nausea and fatigue, as well as abdominal pain and bowel obstruction thought to be related to underlying disease. To date, there is 1 patient with PR, 7 patients with SD and 5 patients with PD, with 1 patient off-trial for patient discretion. PFS is 14 weeks. Patients tolerated this regimen extremely well, with most toxicity attributable to carboplatin alone. Conclusion: The PFS was longer than expected, with a significant proportion of these platinum resistant patients achieving clinical benefit with prolonged stable disease. [61% disease control (CR+PR+SD) rate]

Picoplatin & Pegylated Liposomal Doxorubicin (Doxil®):

  • Final results of a phase I study of picoplatin and pegylated liposomal doxorubicin [e.g. Doxil™] in advanced solid tumor malignancies (2008 ASCO Annual Mtg. Abstr. #2568 ): Picoplatin is a novel, sterically hindered platinum(II) complex designed to circumvent mechanisms of platinum resistance. Given the single agent activity seen in multiple tumor types, we conducted a phase I study of picoplatin in combination with pegylated liposomal doxorubicin (PLD) in patients with advanced solid tumors. The Phase 1 trial enrolled 16 patients with advanced solid tumors who had received up to three prior regimens for metastatic disease. Patients were administered picoplatin followed by liposomal doxorubicin on day one of a 28-day cycle. Four dose levels of picoplatin and pegylated liposomal doxorubicin were tested: 100/20, 100/30, 100/40 and 120/40 (all mg/m2). A total of 62 courses of treatment were delivered to 16 patients with a median number of four cycles per patient. A total of 12 patients were evaluable for response. One patient experienced a CR (primary peritoneal cancer) and four experienced a PR (including three of five patients with ovarian cancer). Hematologic and non-hematologic toxicity were mild. Conclusion: This study suggests that picoplatin and liposomal doxorubicin is an active combination with promising results and can be given at standard dose levels with a minimal increase in toxicity. [41% disease control (CR+PR+SD) rate among evaluable patients]

Weekly Topotecan (Hycamtin™) Monotherapy:

  • Phase II study of weekly topotecan in recurrent ovarian cancer: duration of response based on a prolonged follow-up (ASCO Annual Mtg. Abstr. #16549). Nineteen patients (median age 52 yrs, range 45-72) with EOC who progressed after 3 (11/19 patients = 57.9%), 4 (7/19 patients= 36.8%) or 5 (1/19 patients= 5.3%) previous lines of chemotherapy were treated with Topotecan at the dose of 2.0 mg/m2 via a 30-minute intravenous infusion once every week until disease progression, unacceptable toxicity or when a stability of disease was reached. Results: All patients were evaluable for toxicity and clinical response. 16/19 patients enrolled (84.2%) had stage III-IV disease. Median number of chemotherapy cycles was 7 (range 3 – 12). A total of 107 cycles were administered. Dose reduction was necessary for 13% of the cycles. Main toxicities included anemia (G1-G2=57.9%), leucopenia (G1-G2=15.8%), thrombocytopenia (G1-G2=10.5%) and asthenia (20%). No one showed a CR, while 5/19 patients experienced a PR (26.4%), 6/19 patients experienced SD (31.5%), and 8/19 patients (42.1%) experienced DP. The median PFS was 12 weeks in patients with PR; SD was maintained for a median time of 14 weeks. Conclusion: The rate of patients with ongoing stable disease (31.5%) suggests that the clinical benefit of weekly topotecan may be expected also in patients with no other viable therapeutic options. [57% disease control (CR+PR+SD) rate among evaluable patients]

Azacitidine & Carboplatin:

Combretastatin A4 Phosphate (Zybrestat™) and Bevacizumab (Avastin™):

BSI-201:

Belinostat (PXD101):

SU11248/Sunitinib (Sutent®):

AZD2281 (KU-0059436):

  • AZD2281, a PARP (poly ADP-ribose polymerase) inhibitor with single agent anticancer activity in patients with BRCA deficient ovarian cancer: Results from a phase I study (2008 ASCO Annual Mtg. Abstr. #5510) Thirty-two patients with BRCA-deficient ovarian cancer (i.e., patients with BRCA gene mutations) the majority of whom were platinum resistant/refractory are so far evaluable for response. All evaluable patients had either received treatment for at least 8 weeks (2 cycles) or progressed prior to completion of 2 cycles. Fourteen patients have achieved PR, 13 patients meeting GCIG- CA125 criteria and 10 patients meeting RECIST criteria. Of the responders, 1 patient has been on drug > 56 weeks whilst 7 patients have maintained responses for > 24 weeks. SD was seen in an additional 8 patients, 7 of whom continue on drug and 3 patients had SD > 16 weeks. Responses were seen at all dose levels from 100mg bd and above. Conclusion: AZD2281 is well tolerated and has demonstrated compelling activity in patients with BRCA deficient ovarian cancer. Responses were seen in all patient groups including platinum resistant disease. Updated efficacy data, together with a correlation of potential predictive factors including platinum free interval will be presented on a total planned cohort of 46 patients with BRCA-deficient ovarian cancer. A randomised study in BRCA-deficient ovarian cancer has been planned. [68% disease control (CR+PR+SD) rate among evaluable patients]

Gemcitibine (Gemzar™) & Epirubicin (Ellence™):

Belinostat/PXD101, Carboplatin (Paraplatin®) & Paclitaxel (Taxol™):

Pegylated Liposomal Doxorubicin (Doxil®) & Gemcitabine (Gemzar®):

Pemetrexed/LY231514 (Altima®):

Sorafenib (Nexavar™):

  • Phase II trial of sorafenib in persistent or recurrent epithelial ovarian cancer (EOC) or primary peritoneal cancer (PPC): A Gynecologic Oncology Group (GOG) study (2008 ASCO Annual Mtg. Abstr. #5537). Sorafenib is a tyrosine kinase inhibitor targeting raf and other receptor kinases (VEGF-R, PDGF-R, Flt3, c-KIT). Sorafenib may have anti-angiogenic activity through inhibition of VEGF-R. This phase II study was conducted to assess the activity and tolerability of sorafenib in patients with recurrent EOC. Methods: This was an open label multi-institutional phase II study …. Eligible patients had persistent or recurrent EOC/PPC after 1-2 prior cytotoxic regimens, measurable or detectable (e.g. by CA125) disease, and GOG performance status < 2. Patients were required to have progressed within 12 months of completing platinum based therapy. Treatment consisted of sorafenib 400 mg orally bid until disease progression or prohibitive toxicity. Primary endpoints were PFS at 6 months and toxicity by NCI criteria. Secondary endpoints were tumor response and duration of PFS/OS. Results: 73 patients were enrolled from 10/04 to 5/07 and as of 12/2007, 68 patients are evaluable (2 ineligible and 3 too early) for toxicity. Median age was 60 (range 33-80) years and prior treatment consisted of 1 regimen in 40 patients and 2 regimens in 28 patients. Significant G3 and G4 toxicities included: rash (12 patients), metabolic (10 patients), gastrointestinal (3 patients), cardiovascular (2 patients), and pulmonary (2 patients). No treatment related deaths were recorded. Only patients with measurable disease were used to assess efficacy. Among the 59 patients with measurable disease, 12 survived PFS at least 6 months. Three patients are yet to be determined. Two patients had PR; 20 had SD; 30 had DP, and 7 could not have their tumor assessed. Conclusions: Preliminary results suggest that sorafenib is tolerated in patients with recurrent EOC with dermatologic and metabolic abnormalities being the most common toxicities. Efficacy data is expected to reach maturity and be analyzed in the spring of 2007, and comprehensive results will be presented. [42% disease control (CR+PR+SD) rate among evaluable patients]

Topotecan (Hycamtin™) & Bevacizumab (Avastin™):

  • Phase II prospective study of weekly topotecan and bevacizumab in platinum refractory ovarian cancer or peritoneal cancer (OC) (2008 ASCO Annual Mtg. Abstr. #5551). Patients (pts) with platinum refractory OC have limited treatment options. Bevacizumab, an anti-angiogenesis agent has demonstrated efficacy in recurrent ovarian cancer. Bevacizumab combined with chemotherapy in other solid tumors has improved efficacy compared with bevacizumab or chemotherapy alone. Topotecan, an active drug in recurrent OC has been used in a weekly fashion with less toxicity and more acceptability than a standard 5 day regimen. Topotecan and bevacizumab have non-overlapping toxicities. We studied the efficacy and tolerability of weekly topotecan and bevacizumab in patients with platinum refractory OC. Methods: The primary objectives of this study were to evaluate PFS, OS, OR rate and toxicity of this combination regimen. Eligible pts included those with platinum refractory OC (recurrence < 6 months of platinum therapy) who had received a maximum of 2 prior chemotherapy regimens. Results: Twenty-two pts have been enrolled to date, with 11 pts remaining on study and 18 now evaluable. Best responses for the 18 evaluable pts were: 22.2% PR (n=4), 27.8% SD (n=5), and 50% DP (n=9). Eleven pts went off study due to DP (based on CT scan RECIST criteria [n=6] or general deterioration and/or bowel obstruction [n=5]). Median duration on study for the 18 evaluable pts was 15 wks (range 5-63 weeks). Four pts have had PFS >5 months. The 18 evaluable pts received a total of 91 treatment cycles. No pt went off study due to treatment related toxicity or suffered a bowel perforation. Conclusions: Combination bevacizumab and topotecan administered in a weekly fashion demonstrate good activity in platinum refractory OC with acceptable toxicity. G3-G4 Hematologic or Hypertensive Toxicities. [50% disease control (CR+PR+SD) rate among evaluable patients]

Lapatinib (Tykerb™), Carboplatin (Paraplatin®) & Paclitaxel (Taxol™):

  • Phase I/II lapatinib plus carboplatin and paclitaxel in stage III or IV relapsed ovarian cancer patients (2008 ASCO Annual Mtg. Abstr. #5556). The purpose of this study was to establish the MTD and evaluate DLTs and response to therapy of combination therapy with carboplatin/paclitaxel and lapatinib, an oral dual tyrosine kinase inhibitor of both ErbB1 and ErbB2, in Stage III /IV relapsed ovarian cancer. Methods: This was an open-label, multicenter, phase I/II study of carboplatin/paclitaxel in combination with single agent lapatinib in Stage III/IV relapsed ovarian cancer patients. Measurable disease, adequate organ function and ECOG performance status of 0-2 were required. Results: 25 ovarian cancer patients are enrolled and four are too early to be evaluable. The median age is 57 (range 39-81). The median number of prior therapeutic regimens is 4 (range 1-10). GI toxicities were primarily < grade 2 and were successfully treated with aggressive bowel management. 10 patients (pts) experienced G3 toxicities. 4 pts- leukopenia, 2 pts-neutropenia, 2 pts-hyperglycemia, 2 pts-allergic reactions to carboplatin, 1 pt-thrombocytopenia, 1 pt-lymphopenia, 1 pt-hypokalemia, 1 pt-nausea, 1 pt-diarrhea, 1 pt-bowel obstruction. Response to therapy to date is: CR=21%, PR=29%, SD=29%, PD=21%. Two patients who were in complete remission both stopped IV chemotherapy and were maintained only with lapatinib. One is still in remission after six months and one relapsed. Conclusions: Lapatinib, an oral targeted molecular therapy which inhibits both EGFR 1 and 2 tyrosine kinase activity, can be safely administered with a weekly regimen of carboplatin and paclitaxel in heavily pretreated, ovarian cancer patients. The high response rates seen warrant further investigation. [79% disease control (CR+PR+SD) rate among evaluable patients]

Ifomide, Epirubicin, & Cisplatin:

NKTR-102 (Pegylated irinotecan):

  • Phase I dose finding and pharmacokinetic study of NKTR-102 (PEGylated irinotecan): Early evidence of anti-tumor activity (2008 ASCO Annual Mtg. Abstr. #13518 ). NKTR-102 is a novel pegylated form of irinotecan with superior efficacy against a range of xenografts compared with irinotecan. Sustained tumor inhibition is associated with increased SN38 exposure. A phase I trial of NKTR-102 was conducted to establish the MTD and to characterize safety and PK in patients (pts) with refractory solid tumors. No CTC Grade 4 toxicity was observed. G3 diarrhea was dose limiting. Other toxicities included transient uncomplicated G3 neutropenia and transient infusion related visual disturbance. PK data are available for 12 pts. Two partial responses were observed in pts with advanced cervical cancer and small cell lung cancer. Anti-tumor activity was seen in 4 other pts; ovarian: CA-125 decreased from 2557 to 518, Hodgkin’s disease: 28% radiologic improvement with symptomatic benefit, adrenocortical: cortisol levels normalized, metabolic response by PET, esophageal: CEA decreased from 35.5 to 13.6, metabolic response by PET. Conclusions: NKTR-102 shows early evidence of activity in a wide spectrum of tumors. Cumulative SN38 exposure is 1.2 to 6.5 fold higher than that predicted for irinotecan. Toxicity is manageable; diarrhea (not neutropenia) is dose limiting.

ON 01910.Na:

  • Phase I study of ON 01910.Na, a novel polo-like kinase 1 pathway modulator, administered as a weekly 24-hour continuous infusion in patients with advanced cancer (2008 ASCO Annual Mtg. Abstr. #2515). ON 01910.Na induces G2/M cell cycle arrest, apoptosis, and cell death in a broad spectrum of cancer cells, but not in non-neoplastic cells. In vitro, cell killing is dependent on drug exposure time. Based on these preclinical findings, a weekly 24hr continuous infusion (CI) study to determine safety and MTD of ON 01910.Na was initiated. Methods: Patients with advanced cancers received ON 01910.Na as a weekly 24hr CI. Twenty-three pts (7:16 M:F, 45-80 yrs) have received ON 01910.Na. G2 toxicities (2-grade increase over baseline) included fatigue (3 pts) and anorexia (1 pt). Fatigue (11/23 pts) was the most common side effect, with no G3 or greater fatigue observed. Overall, three G3 events occurred, none of which were drug-related. The best response was a pt with advanced ovarian cancer who maintained stable disease for 36 wks of treatment. Conclusions: ON 01910.Na is well tolerated as a weekly 24h continuous infusion. In the dose range studied, the drug exhibited non-linear kinetics with rapid attainment of plasma concentrations that are cytotoxic to cancer cells in vitro, but have limited end-organ toxicity in vivo. Study data continues to accrue, and we expect to recommend a phase II dose shortly. Further analysis and combination phase I studies are planned.

BAY 73-4506:

  • Phase I study of BAY 73-4506, an inhibitor of oncogenic and angiogenic kinases, in patients with advanced solid tumors: Final results of a dose-escalation study (2008 ASCO Annual Mtg. Abstr. #2558 ). BAY 73-4506 is a potent tyrosine kinase inhibitor of receptor tyrosine kinases (VEGFR, PDGF, RET, KIT, FGFR) and serine/threonine kinases (raf and p38MAPK). In tumor xenograft models, BAY 73-4506 demonstrated a broad spectrum antitumor activity. Methods: This phase I study was a dose-escalation trial investigating the safety, PK, and pharmacodynamic (PD) profile of BAY 73-4506, given orally in 21 days on/7 days off cycles, until discontinuation due to toxicity or tumor progression. PK was assessed on days 1 and 21 of cycle 1. PD markers including DCE-MRI, soluble VEGFR-2 (sVEGFR-2) and VEGF plasma levels were assessed at each cycle. Tumor response was evaluated as per RECIST. Results: 52 patients (pts) with solid tumors and progressive disease were enrolled and treated with doses of 10 to 220 mg once daily. Frequent tumor types included colorectal cancer (CRC) (31%), malignant melanoma (10%), and ovarian cancer (10%). The median treatment duration was 49.5 days (min. 3, max. 609). Drug-related adverse events (AEs) of all grades reported in >20% of pts were hoarseness (54%), dermatological toxicities (50%; CTC G3-G4: 13%), mucositis (35%), diarrhea (25%; CTC 3: 2%), fatigue (23%; CTC 3: 2%), and hypertension (23%; CTC 3: 6%). Treatment-related AEs leading to dose reduction, interruption or discontinuation were hand foot skin reaction (15%), diarrhea (8%), and thrombopenia (6%). Of the 33 evaluable pts, 9% achieved a partial response (PR), 64% had stable disease (SD), at least 7 weeks after start of treatment, and 48% had SD or PR for more than 11 weeks. Conclusions: The recommended phase II dose for BAY 73-4506 is 160 mg daily, using the 21 days on/7 days off treatment schedule. Clinical activity (PR+SD) has been demonstrated in 73% of the evaluable pts. An extension cohort (dose level 160 mg) has been started.

Epirubicin Improves Overall Survival Better Than Ifosfamide When Combined with Paclitaxel and Cisplatin

Epirubicin (Ellence®) produced longer median overall survival (OS) than ifosfamide (Ifex®) in a recent phase II randomized clinical trial comparing (i) cisplatin, paclitaxel and ifosfamide, with (ii) cisplatin, paclitaxel and epirubicin, in newly diagnosed advanced epithelial ovarian cancer patients. In this trial, patients with histologically proven epithelial ovarian cancer were randomly assigned to receive first-line polychemotherapy with cisplatin/paclitaxel/epirubicin (CEP arm) or cisplatin/paclitaxel/ifosfamide (CIP arm) for six cycles every 21 days. Two hundred and eight patients were randomised between the two treatment arms. The Phase II clinical trial finds were as follows:

  • After a median follow-up of 82 months, median overall survival (OS) was 51 months in the CIP arm, and 65 months in the CEP arm; and
  • 5-year survival rates were 43% in the CIP arm, and 50% in the CEP arm.

The trial investigators note that the OS findings seem longer in duration than is commonly reported, especially considering that more than 50% of the newly diagnosed advanced ovarian cancer patients were suboptimally debulked or cytoreduced after their first surgery. The trial investigators concluded that this unexpected finding might be a consequence of the close surgical surveillance and aggressive chemotherapeutic approach.

[Source: “A phase II randomised clinical trial comparing cisplatin, paclitaxel and ifosfamide with cisplatin, paclitaxel and epirubicin in newly diagnosed advanced epithelial ovarian cancer: long-term survival analysis;” Fruscio R. et. al.; Br J Cancer. 2008 Feb 26;98(4):720-7.]

Comment: Although small in size, this Phase II randomized clinical trial suggests that aggressive surgical intervention followed by aggressive polychemotherapy (involving epirubicin or ifosfamide in tandem with paclitaxel and cisplatin) may increase overall survival in newly diagnosed, advanced-stage ovarian cancer survivors. The findings of at least one major clinical study cite that optimal cytoreduction, as a stand-alone independent factor, provides up to a 50% increase in actuarial survival. In the U.S., an “optimal” cytoreduction is generally defined as a surgical procedure that results in 1 centimeter or less of macroscopic cancer present within the body after surgery. The surprising results of the study discussed above seem to indicate that a suboptimal cytoreduction or debulking surgery followed by aggressive polychemotherapy may be beneficial in extending overall survival in newly diagnosed, advanced-stage ovarian cancer survivors. The issue of what measure should be used to define an “optimal” cytoreduction or debulking is not without controversy with the ovarian cancer arena.