2011 ASCO: Matching Targeted Therapies To Specific Tumor Gene Mutations Key to Personalized Cancer Treatment

Customizing targeted therapies to each tumor’s molecular characteristics, instead of a “one-size-fits-all” approach by tumor type, may be more effective for some types of cancer, according to research presented today at the American Society of Clinical Oncology annual meeting by the M.D. Anderson Cancer Center. In patients with end-stage disease, matched patients achieved a 27% response rate, versus 5% in those unmatched.

Customizing targeted therapies to each tumor’s molecular characteristics, instead of a “one-size-fits-all approach” by tumor type, may be more effective for some types of cancer, according to research conducted by The University of Texas M.D. Anderson Cancer Center.

Apostolia M. Tsimberidou, M.D., Ph.D., Associate Professor, Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, Texas

M.D. Anderson’s phase I clinical study findings were presented today on the opening press program of the 47th Annual Meeting of the American Society of Clinical Oncology. Apostolia-Maria Tsimberidou, M.D., Ph.D., associate professor in the M.D. Anderson Department of Investigational Cancer Therapeutics, and the principal investigator of the study, presented the data.

Marking the largest scale on which this approach has been examined to date, the study analyzed the results of matching targeted therapies with specific gene mutations in patients. The data indicated that this strategy was associated with higher rates of response, survival and failure-free survival than observed in non-matched patients.

Pairing Patient and Treatment

“This preliminary study strongly suggests that molecular analysis is needed to use the right drug for the right patient. Up to this point, we have treated tumor types, but this study shows we cannot treat all patients with a tumor type the same way. We need to take into consideration a number of factors, and this study suggests that a personalized approach is needed to improve clinical outcomes for patients with cancer,” said Tsimberidou.

The identification of pathways involved in carcinogenesis, metastasis and drug resistance; new technologies enabling tumor molecular analysis; and the discovery of targeted therapies have stimulated research focusing on the use of targeted agents as part of a personalized medicine approach, she said.

“Over the past decades, a personalized medicine approach using Gleevec has changed the way we treat chronic myeloid leukemia, as well as survival rates,” said Razelle Kurzrock, M.D., professor and chair of the M.D. Anderson Department of Investigational Cancer Therapeutics. “We wanted to apply a similar approach to solid tumors.”

“Ultimately, to best match treatments to patients and offer the most therapeutic benefit, assessing a patient’s molecular markers has to become the standard at diagnosis. … 

This study affirms what we in the cancer community have been talking about for a decade – matching drugs to patients. The time is now. The drugs are here. The technology is here, and with our program at M.D. Anderson we can bring the two together in hopes to offer the most personalized care for our patients. …”

–Razelle Kurzrock, M.D., Professor & Chair, Department of Investigational Cancer Therapeutics, University of Texas M.D. Anderson Cancer Center

Research Methods and Results

In the initial analysis, Tsimberidou analyzed 1,144 patients with metastatic or inoperable cancer who underwent testing for molecular aberrations at M.D. Anderson. Their median age was 58, and the median number of prior treatments was four. Of these patients, 460 had one or more gene aberrations, including:

  • 10 percent with a PIK3CA mutation;
  • 18 percent with a KRAS mutation;
  • 8 percent with a NRAS mutation;
  • 17 percent with a BRAF mutation;
  • 3 percent with an EGFR mutation;
  • 2 percent with a CKIT mutation;
  • 21 percent with a PTEN loss; and
  • 37 percent with a p53 mutation

Patients with gene aberrations were treated on clinical trials with matched targeted agents, when available. Regimens included one or more therapies targeting PIK3CA, mTOR, BRAF, MEK, multikinases, KIT or EGFR. Outcomes of patients with gene aberrations treated with matched therapy were compared with those patients with gene aberrations who were not treated with matched therapy because of issues such as eligibility, study availability; insurance coverage and/or logistical problems with the study calendar.

For the 175 patients with one aberration, the response rate was 27 percent with matched targeted therapy. The response rate was 5 percent in 116 patients when treated with non-matched therapy.

Patients who received matched targeted therapy had median survival of 13.4 months, while median survival for patients treated with unmatched targeted therapy was nine months. Median failure-free survival in patients who received matched targeted therapy was 5.2 months, compared to 2.2 months for patients who received unmatched targeted therapy.

Further Research Needed

These preliminary results merit further investigation and confirmatory, prospective studies are needed, especially because the study was not a randomized study and therefore biases could influence the results.

“M.D. Anderson’s goal is to better understand the biology involved in each patient’s carcinogenesis by testing each tumor for genetic abnormalities driving tumor growth to guide treatment selection. This strategy will lead to the optimization of personalized therapy,” Tsimberidou said.

Another goal is to match targeted therapies to patients earlier in treatment.

“When Gleevec was first introduced, it was tested in patients in blast crisis and the response rate was about 15 percent. In contrast, when tested in the front line setting, and with the introduction of similar but increasingly potent second- and third-generation drugs, patients’ response rate was close to 100 percent, and now their expected survival is 25 years and counting,” said Kurzrock. “Ultimately, to best match treatments to patients and offer the most therapeutic benefit, assessing a patient’s molecular markers has to become the standard at diagnosis.”

About the Phase I Program – The Time is Now

The M.D. Anderson’s Phase I program is the largest of its kind and accounts for the majority – but not all – of the institution’s earliest clinical studies. In 2010, of the 11,000 patients who participated in M.D. Anderson clinical trials, more than 1,150 were enrolled in one of the 120 Phase I trials in the program.

Currently, tumors are tested for up to 12 molecular aberrations, but at the rate technology is rapidly advancing, Kurzrock expects that number to climb to more than 100 in the near future.

Patients treated in the Phase I Program are typically very ill and all other approved therapies have failed them. Yet they are “fighters” who are willing to try anything, including studies not specific to their diagnosis to test the effectiveness of a new drug, drug combination or delivery method, said Kurzrock.

“This study affirms what we in the cancer community have been talking about for a decade – matching drugs to patients,” said Kurzrock. “The time is now. The drugs are here. The technology is here, and with our program at M.D. Anderson we can bring the two together in hopes to offer the most personalized care for our patients.”

In addition to Tsimberidou and Kurzrock, other authors on the all-M.D. Anderson study included N. G. Iskander, David S. Hong, M.D., Jennifer J. Wheler, M.D., Siqing Fu, M.D., Ph.D., Sarina A. Piha-Paul, M.D., Aung Naing, M.D., Gerald Falchook, Filip Janku, M.D., Ph.D., all assistant professors of the Department of Investigational Cancer Therapeutics; Raja Luthra, Ph.D., professor, Department of Hematopathology, Research and Sijin Wen, Ph.D., Division of Quantitative Sciences.

Libby’s H*O*P*E*™ Commentary — Use of Molecular Profiling and Chemosensitivity Testing To Determine Individualized Ovarian Cancer Treatment

It is wonderful that various medical research institutions, including M.D. Anderson, are beginning to match targeted therapies to a patient’s specific molecular tumor characteristics. This approach is generally referred to as “molecular profiling,” and it represents one promising method of matching an individual cancer patient to an effective therapy. As noted in the related Libby’s H*O*P*E*™ postings set forth below, there are several medical and scientific institutions which are pursuing development of molecular profiling for clinical study use. In the most recent related posting listed below, we discuss the molecular profile testing that is commercially available through The Clearity Foundation and Caris Life Sciences.

In the future, it may be helpful to use a form of chemosensitivity testing (e.g., the type of testing provided by Precision Therapeutics, Rational Therapeutics, and the Weisenthal Cancer Group), which is based upon the measurement of actual cancer cell death, as a second method to match a cancer patient to a potential drug or drug combination within the context of a clinical study. In fact, we would like to see a future prospective, randomized ovarian cancer clinical trial in which enrolled women are provided with treatment after assignment to one of three clinical trial arms:  (i) treatment based upon the standard of care (e.g., paclitaxel and carboplatin), (ii) treatment based upon molecular profiling, or (iii) treatment based upon chemosensitivity testing.  This type of study may uncover additional ovarian cancer treatment insights (both molecular and functional) with respect to the most lethal gynecologic cancer, while ultimately helping women with forms of the disease that may not possess a known molecular characteristic that is potentially “targetable” by an existing clinical trial drug or compound.

This combination of “bottom-up” scientific research (i.e., molecular profiling) performed side-by-side with “top-down” research (i.e., chemosensitivity testing) may represent an effective and efficient approach — albeit provocative — for evaluation of optimal personalized ovarian cancer treatment.

It is important to note that Libby’s H*O*P*E*™ and its founder Paul Cacciatore do not receive financial renumeration or benefit of any kind from the companies referred to in the paragraphs above.

About the University of Texas M.D. Anderson Cancer Center

The University of Texas M.D. Anderson Cancer Center in Houston ranks as one of the world’s most respected centers focused on cancer patient care, research, education and prevention. MD Anderson is one of only 40 comprehensive cancer centers designated by the National Cancer Institute. For seven of the past nine years, including 2010, M.D. Anderson has ranked No. 1 in cancer care in “America’s Best Hospitals,” a survey published annually in U.S. News & World Report.

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Related Libby’s H*O*P*E* Postings:

Novel Targeted Gene Therapies Use Diphtheria Toxin To Fight Ovarian Cancer; One Clinical Trial Underway

Two separate research teams reported promising results last week based upon preclinical studies involving the use of diphtheria toxin to fight ovarian cancer. … A targeted gene therapy was utilized in both studies, wherein a gene fragment capable of producing diptheria toxin was combined with a nanoparticle which was targeted against a unique or overexpressed genetic characteristic of the ovarian cancer tumor cells. Both research teams reported significant reduction in ovarian cancer tumor mass and extended survival for the treated mice. Based upon these findings, one research team already announced the opening of a Phase I/II clinical trial which will test the novel therapy on patients with advanced stage ovarian cancer.

Targeted Gene Therapy In the Fight Against Ovarian Cancer

The peritoneal cavity is a common site of ovarian cancer and accompanying ascites caused by the disease. Ascites is an abnormal buildup of fluid in the peritoneal cavity that causes swelling.  Malignant tumor cells may be found in the ascites fluid in connection with late stage ovarian cancer.  Massive ascites and the related abdominal distention can cause anorexia, nausea, vomiting and respiratory difficulties, and negatively impact the patient’s quality of life. Ovarian cancer patients frequently experience disease involvement of the pelvic and retroperitoneal lymph nodes as well. The standard primary treatment of patients with advanced stage ovarian cancer is cytoreductive surgery followed by platinum drug and taxane drug doublet chemotherapy. Despite this aggressive approach, there is a high rate of disease recurrence. Although discovery of several other active nonplatinum cytotoxic agents has improved outcome, long-term survival rates are low. Success of traditional chemotherapy has been limited by drug resistance and lack of specificity with respect to disease formation and progression. Thus, novel “targeted” ovarian cancer therapies that achieve improved long-term disease control with lower toxicity are desperately needed.

A so-called “targeted therapy” utilizes drugs or other medically manufactured substances (e.g., small molecule drugs or monoclonal antibodies) to block the growth and spread of cancer by interfering with specific molecules involved in cancer tumor growth and progression.  By identifying and selectively focusing upon molecular and cellular changes or unique genetic characteristics that are specific to cancer, targeted cancer therapies may be more effective than other types of treatment, including chemotherapy, and less harmful to normal cells.

It is possible for a targeted therapy to incorporate a gene therapy. Gene therapy is an experimental treatment that involves the introduction of genetic material (DNA or RNA) into a human cell to fight a disease such as cancer.  When both therapeutic approaches are combined by researchers, a “targeted gene therapy” is the result.  A targeted gene therapy is an attractive approach to controlling or killing human cancer cells only if the therapy can selectively identify and exploit the genetic and epigenetic alterations in cancer cells, without harming normal cells that do not possess such alternations.

Two separate research groups reported promising results last week based upon preclinical studies involving the use of diphtheria toxin to fight ovarian cancer.  The toxin is produced by a deadly bacterium (Corynebacterium diphtheriae).  A targeted gene therapy was utilized in both studies, wherein a gene fragment capable of producing diptheria toxin was combined with a nanoparticle which was targeted against a unique or overexpressed genetic characteristic of the ovarian cancer tumor cells.  Both research teams reported significant reduction in ovarian cancer tumor mass and extended survival for the treated mice. Based upon these findings, one research team already announced the opening of a Phase I/II clinical trial which will test the novel therapy on patients with advanced stage ovarian cancer.

MIT-Lankenau Institute Researchers Use Diphtheria Toxin Gene Therapy To Target Overexpression Of The MSLN & HE4 Ovarian Cancer Genes.

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Daniel Anderson, Ph.D., Research Associate, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology

The first study, which appears in the August 1 issue of the journal Cancer Research, was conducted by a team of researchers from the Massachusetts Institute of Technology (MIT) and the Lankenau Institute of Medical Research (Lankenau Institute). In this study, the researchers used a nanoparticle as a delivery vehicle (or vector) for DNA that encodes a diphtheria toxin suicide protein (DT-A).  The novel nanoparticles are made with positively charged, biodegradable polymers known as poly(beta-amino esters). When mixed together, these polymers can spontaneously assemble with DNA to form nanoparticles. The polymer-DNA nanoparticle can deliver functional DNA when injected into or near the targeted tissue.

The nanoparticle carrying the DT-A is designed to target overexpression of two genes (mesothelin (MSLN) and HE4 (or WFDC2)) that are highly active in ovarian tumor cells, but not in normal cells. Once inside an ovarian cancer tumor cell, the DT-A disrupts the tumor cell’s ability to manufacture critical life sustaining proteins, thereby causing cell death.  Accordingly, the choice of the DT-A fragment of a diptheria toxin gene ensures high ovarian cancer cell killing activity.  It also avoids unintended toxicity to normal cells because the DT-A released from destroyed ovarian cancer cells is not able to enter normal neighboring tissue cells in the absence of the DT-B fragment which was excluded from the original nanoparticle delivery system or vector.

As part of this study, researchers administered DT-A nanoparticles directly into the peritoneal cavity – which encases abdominal organs such as the stomach, liver, spleen, ovaries and uterus – of mice xenografted with primary and metastatic ovarian tumors.  Ovarian cancer is known to initially spread throughout the peritoneal cavity, and current therapeutic approaches in humans include direct injection into the peritoneal space, thereby targeting the therapy to the ovaries and nearby tissues where tumors may have spread.

“… [The researchers] discovered that the intraperitoneal (IP) administration of DT-A nanoparticles resulted in a significant reduction in ovarian tumor mass and extended survival for the treated mice.  The researchers also found that the targeted gene-therapy treatment was as effective, and in some cases more effective, than the traditional chemotherapy combination of cisplatin and paclitaxel. …”

langerrobert

Robert S. Langer is the David H. Koch Institute for Integrative Cancer Research Professor (there are 14 Institute Professors at MIT; being an Institute Professor is the highest honor that can be awarded to a faculty member). Dr. Langer has written approximately 1,050 articles. He also has approximately 750 issued and pending patents worldwide. Dr. Langer’s patents have been licensed or sublicensed to over 220 pharmaceutical, chemical, biotechnology and medical device companies. He is the most cited engineer in history.

Sawicki

Janet Sawicki, Ph.D., Professor, Lankenau Institute of Medical Research. Dr. Sawicki also serves as an Associate Professor at the Kimmel Cancer Center of Thomas Jefferson University. Her ovarian cancer research is funded by the National Institutes of Health, the U.S. Department of Defense, the Sandy Rollman Foundation, the Teal Ribbon Ovarian Cancer Foundation, and the Kaleidoscope of Hope Foundation.

Daniel Anderson, Ph.D., research associate in the David H. Koch Institute for Integrative Cancer Research at MIT and a senior author of the paper, and others from MIT, including Institute Professor Robert Langer, along with researchers from the Lankenau Institute, led by Professor Janet Sawicki, discovered that the intraperitoneal (IP) administration of DT-A nanoparticles resulted in a significant reduction in ovarian tumor mass and extended survival for the treated mice.  The researchers also found that the targeted gene-therapy treatment was as effective, and in some cases more effective, than the traditional chemotherapy combination of cisplatin and paclitaxel. Furthermore, the novel therapy did not have the toxic side effects of chemotherapy because the diptheria toxin gene is engineered to function in ovarian cells but is inactive in normal cell types.

Based upon these finding, the MIT and Lankenau Institute researchers concluded that IP administration of DT-A nanoparticles, combined with designed targeting of those nanoparticles against ovarian tumor cell gene (MSLN & HE4) expression, holds promise as an effective therapy for advanced-stage ovarian cancer. According to Anderson, human clinical trials could start, after some additional preclinical studies, in about 1 to 2 years.  Currently ovarian cancer patients undergo surgery followed by chemotherapy. In many cases, the cancer returns after treatment.  Disease recurrence is problematic because there are no curative therapies for advanced-stage tumors.

For several years, the MIT-Lankenau Institute team worked to develop the DT-A nanoparticles as an alternative to viruses, which are associated with safety risks. In addition to ovarian cancer, these nanoparticles have demonstrated treatment potential for a variety of diseases, including prostate cancer and viral infection. “I’m so pleased that our research on drug delivery and novel materials can potentially contribute to the treatment of ovarian cancer,” Langer said. In future studies, the team plans to examine the effectiveness of nanoparticle-delivered diphtheria toxin genes in other types of cancer, including brain, lung and liver cancers.

Other MIT authors of the paper are recent MIT Ph.D. recipients Gregory Zugates and Jordan Green (now a professor at John’s Hopkins University), and technician Naushad Hossain. The research was funded by the Department of Defense and the National Institutes of Health.

Israeli Researchers Use Diphtheria Toxin Gene Therapy To Target Overexpression Of The H19 Ovarian Cancer Gene.

The second study was conducted by Israeli researchers and was published August 6 online ahead of print in the Journal of Translational Medicine.

In the provisional study report, the researchers note that based upon earlier studies from their team and others, the H19 gene has emerged as a candidate for cancer gene therapy. The H19 gene is expressed at substantial levels in ovarian cancer tumor cells, but is nearly undetectable in surrounding normal tissue cells.  Although the Israeli research team acknowledges that the exact function of H19 is the subject of past debate, it notes that recent data suggests a role for H19 in promoting cancer progression, angiogenesis and metastasis.

As a first step, Israeli researchers tested H19 gene expression in ovarian cancer cells obtained from the ascites fluid of 24 patients, and established that H19 expression levels were detected in 90% of the tested patients. Of those patients with positive H19 expression, 76% showed a moderate or high level of expression, while 24% showed a low level of expression.

Next, the researchers created a DT-A nanoparticle similar to the one created by the MIT/Lankenau research team as described above, except the Israeli nanoparticle was designed to target H19 overexpression within ovarian cancer cells.  The therapeutic effect of the DT-A/H19 nanoparticles was first tested in vitro against various ovarian cancer cell lines and cells obtained from patient ascites fluid.  The researchers determined that the DT-A/H19 nanoparticle therapy caused ovarian cancer cell death.  The therapeutic effect of the DT-A nanoparticles was tested in vivo by injecting the DT-A nanoparticles into mice xenografted with ovarian cancer tumors. The researchers estimate that the DT-A nanoparticle therapy reduced ovarian cancer tumor growth in the treated mice by 40%.

Based upon these finding, the researchers note that although the study report issued is provisonal, it is their working hypothesis that intraperitoneal administration of DT-A/H19 nanoparticles holds the potential to (1) reach ascites tumor cells, (2) deliver its intracellular toxin without targeting normal tissue cells, and (3) reduce tumor burden & fluid accumulation; and therefore, improve the patient’s quality of life, and hopefully, prolong her survival.

  • DT-A/H19 Nanoparticle Therapy Administered To An Israeli Patient On A Compassionate Use Trial Basis

In the provisional study report, the researchers state that the targeted gene therapy was administered to an Israeli patient with advanced, recurrent ovarian cancer, who qualified for compassionate use treatment under Israeli regulatory rules.  Specifically, the patient’s intraperitoneal ovarian cancer metastases and ascites were treated with the DT-A/H19 nanoparticle therapy after the failure of conventional chemotherapy. The results of the single patient compassionate use trial suggest that the drug caused no serious adverse events at any drug dosage level.  Moreover, the patient experienced (1) a 50% decrease in serum cancer marker protein CA-125, (2) a significant decrease in the number of cancerous cells in the ascites, and (3) a clinical improvement as reported by her doctors.  It is reported that the patient’s quality of life increased during the course of treatment and her condition continues to be stable, with no new cancerous growths.

  • Phase I/II Clinical Trial To Test DT-A/H19 Nanoparticle Therapy (BC-819) In the U.S. & Israel

The DT-A/H19 nanoparticle therapy is being developed commercially by BioCancell Therapeutics, Inc (BioCancell) Recently, BioCancell announced the opening of a clinical trial to test the DT-A/H19 nanoparticle therapy (also referred to as BC-819) in patients with advanced stage ovarian cancer.  The clinical trial is entitled, Phase 1/2a, Dose-Escalation, Safety, Pharmacokinetic, and Preliminary Efficacy Study of Intraperitoneal Administration of DTA-H19 in Subjects With Advanced Stage Ovarian Cancer, and the trial investigators are recruiting patients in the U.S. and Israel as indicated below.

University of Pennsylvania Medical Center [Abramson Cancer Center] (Recruiting)
Philadelphia, Pennsylvania, United States, 19104-6142
Contact: Lana E. Kandalaft, Pharm.D, PhD – 215-537-4782 (lknd@mail.med.upenn.edu)
Principal Investigator: George Coukos, M.D., Ph.D.

Massey Cancer Center (Not yet recruiting)
Richmond, Virginia, United States, 23298-0037
Contact: Jane W. Baggett, RN 804-628-2360 (jbaggett@mcvh-vcu.edu)
Principal Investigator: Cecelia H. Boardman, M.D.

The Edith Wolfson Medical Center (Recruiting)
Holon, Israel
Contact: Pnina Nir (972)-52-8445143 (pninanir@wolfson.health.gov.il)
Principal Investigator: Tally Levy, M.D.

Hadassah University Hospital (Recruiting)
Jerusalem, Israel
Contact: Zoya Bezalel (972)-2-6776725 (zoyab@hadassah.org.il)
Principal Investigator: David Edelman, MD

Meir Hospital (Recruiting)
Kfar Saba, Israel
Contact: Tal Naderi 09-7472213 (Ta.INadiri@clalit.org.il)
Principal Investigator: Ami Fishman, MD

In the provisional study report, the Israeli researchers discuss the importance of collecting data regarding the correlation between the level of ovarian cancer cell H19 expression and the efficacy of the treatment as part of the clinical trial discussed above.  Based upon accrued future clinical trial data, the researchers believe that they will be able to identify in advance patients that will respond to this novel therapy, as well as non-responders who are resistant to all known therapies, thereby avoiding treatment failure and unnecessary suffering and cost.

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M.D. Anderson’s EphA2-Targeted Therapy Delivers Chemo Directly to Ovarian Cancer Cells

With a novel therapeutic delivery system, a research team led by scientists at The University of Texas M. D. Anderson Cancer Center has successfully targeted a protein that is over-expressed in ovarian cancer cells. Using the EphA2 protein as a molecular homing mechanism, chemotherapy was delivered in a highly selective manner in preclinical models of ovarian cancer, the researchers report in the July 29 issue of the Journal of the National Cancer Institute. … In the models, the therapy inhibited tumor growth in treated mice by 85 percent – 98 percent compared to control mice. … [Anil] Sood said, “We are gearing up to bring it to phase I clinical trials. A lot of the safety studies are well under way or nearing completion and we anticipate that this drug will enter clinical trials within the next few months.”

M. D. Anderson-led team finds potent antitumor activity with a monoclonal antibody-chemotherapy combination

With a novel therapeutic delivery system, a research team led by scientists at The University of Texas M. D. Anderson Cancer Center has successfully targeted a protein that is over-expressed in ovarian cancer cells. Using the EphA2 protein as a molecular homing mechanism, chemotherapy was delivered in a highly selective manner in preclinical models of ovarian cancer, the researchers report in the July 29 issue of the Journal of the National Cancer Institute.

EphA2 is attractive for such molecularly targeted therapy because it has increased expression in ovarian and other cancers, including breast, colon, prostate and non-small cell lung cancers and in aggressive melanomas, and its expression has been associated with a poor prognosis.

Anil K. Sood, M.D., professor and in the Departments of Gynecologic Oncology and Cancer Biology at the Univ. of Texas M. D. Anderson Cancer Center

Anil K. Sood, M.D., professor in the Departments of Gynecologic Oncology and Cancer Biology at the Univ. of Texas M. D. Anderson Cancer Center

“One of our goals has been to develop more specific ways to deliver chemotherapeutic drugs,” said senior author Anil K. Sood, M.D., professor and in the Departments of Gynecologic Oncology and Cancer Biology at M. D. Anderson. “Over the last several years we have shown that EphA2 is a target that is present quite frequently in ovarian and other cancers, but is either present in low levels or is virtually absent from most normal adult tissues. EphA2’s preferential presence on tumor cells makes it an attractive therapeutic target.”

The researchers used a carrier system to deliver chemotherapy directly to ovarian cancer cells. The immunoconjugate contains an anti-EphA2 monoclonal antibody linked to the chemotherapy drug monomethyl auristatin phenylalanine (MMAF) through the non-cleavable linker maleimidocaproyl. Research has shown that auristatins induce cell cycle arrest at the G – M border, disrupt microtubules and induce apoptosis (programmed cell death) in cancer cells.

The investigators evaluated the delivery system’s specificity in EphA2-positive HeyA8 and EphA2-negative SKMel28 ovarian cancer cells through antibody-binding and internalization assays. They also assessed viability and apoptosis in ovarian cancer cell lines and tumor models and examined anti-tumor activity in orthotopic mouse models with mice bearing HeyA8-luc and SKOV3ip1 ovarian tumors.

According to Sood, who is also co-director of both the Center for RNA Interference and Non-Coding RNA and the Blanton-Davis Ovarian Cancer Research Program at M. D. Anderson, the immunoconjugate was highly specific in delivering MMAF to the tumor cells that expressed EphA2 while showing minimal uptake in cells that did not express the protein. In the models, the therapy inhibited tumor growth in treated mice by 85 percent – 98 percent compared to control mice.

“Once we optimized the dosing regimen, the drug was highly effective in reducing tumor growth and in prolonging survival in preclinical animal models,” Sood said. “We actually studied bulkier masses because that is what one would see in a clinical setting where there are pre-existent tumors, and even in this setting the drug was able to reduce or shrink the tumors.”

As for future research with the EphA2-silencing therapy, Sood said, “We are gearing up to bring it to phase I clinical trials. A lot of the safety studies are well under way or nearing completion and we anticipate that this drug will enter clinical trials within the next few months.”

He added that his group is simultaneously conducting preclinical testing on other chemotherapy drugs to determine which agents might combine well with the immunoconjugate used in the current study.

“There is growing interest in molecularly targeted therapy so that we are not indiscriminately killing normal cells,” Sood noted. “The goal is to make the delivery of chemotherapy more specific. The immunoconjugate we used is in a class of drugs that is certainly quite attractive from that perspective.”

Research was funded by NCI-DHHS-NIH T32 Training Grant (T32 CA101642 to A.M.N.). This research was funded in part by support from M. D. Anderson’s ovarian cancer SPORE grant (P50 CA083639), the Marcus Foundation, the Gynecologic Cancer Foundation, the Entertainment Industry Foundation, the Blanton-Davis Ovarian Cancer Research Program, and Sood’s Betty Ann Asche Murray Distinguished Professorship.

Co-authors with Sood are Jeong-Won Lee, Hee Dong Han, Mian M. K. Shahzad, Seung Wook Kim, Lingegowda S. Mangala, Alpa M. Nick, Chunhua Lu, Rosemarie Schmandt, Hye-Sun Kim, Charles N. Landen, Robert L. Coleman, all of M. D. Anderson’s Department of Gynecologic Oncology; Robert R. Langley, of M. D. Anderson’s Department of Cancer Biology; Jeong-Won Lee, also of the Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Mian M. K. Shahzad, also of the Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas; Hye-Sun Kim, also of the Department of Pathology, Cheil General Hospital and Women’s Healthcare Center, Kwandong University College of Medicine, Seoul, Korea; and Shenlan Mao, John Gooya, Christine Fazenbaker, Dowdy Jackson, and David Tice , all of MedImmune, Inc., Gaithersburg, Maryland.

Source: EphA2-Targeted Therapy Delivers Chemo Directly to Ovarian Cancer Cells – M. D. Anderson-led team finds potent antitumor activity with a monoclonal antibody-chemotherapy combination, M.D. Anderson News Release, 29 Jul. 09 [summarizing the findings of Lee JW, Han HD, Shahzad MM et. al. EphA2 Immunoconjugate as Molecularly Targeted Chemotherapy for Ovarian Carcinoma. J Natl Cancer Inst. 2009 Jul 29. [Epub ahead of print]].

Addition of Dasatinib (Sprycel) to Standard Chemo Cocktail May Enhance Effect in Certain Ovarian Cancers

“The addition of a chemotherapeutic drug for leukemia to a standard regimen of two other chemotherapy drugs appears to enhance the response of certain ovarian cancers to treatment, according to a pre-clinical study led by researchers in the Duke Comprehensive Cancer Center.  ‘We know that a pathway called SRC is involved in cell proliferation in certain types of cancers, including some ovarian cancers,’ said Deanna Teoh, MD, a fellow in gynecologic oncology at Duke and lead investigator on this study.  ‘By examining gene expression data, we determined that the combination of the leukemia drug dasatinib (Sprycel) made carboplatin and paclitaxel more effective in cell lines with higher levels of SRC expression and SRC pathway deregulation.’ …”

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Angeles Secord, MD, Gynecologic Oncologist, Duke University Medical Center & Senior Investigator on this study. Deanna Teoh, MD, Gynecologic Oncologist at Duke was the lead investigator.

“The addition of a chemotherapeutic drug for leukemia to a standard regimen of two other chemotherapy drugs appears to enhance the response of certain ovarian cancers to treatment, according to a pre-clinical study led by researchers in the Duke Comprehensive Cancer Center.

‘We know that a pathway called SRC is involved in cell proliferation in certain types of cancers, including some ovarian cancers,’ said Deanna Teoh, MD, a fellow in gynecologic oncology at Duke and lead investigator on this study.

‘By examining gene expression data, we determined that the combination of the leukemia drug dasatinib (Sprycel®) made carboplatin and paclitaxel more effective in cell lines with higher levels of SRC expression and SRC pathway deregulation.’

That synergistic effect, in which drugs used in combination strengthen each other’s efficacy, was absent when low SRC expression and low SRC pathway deregulation were present, Teoh said.

‘These findings indicate that we may be able to direct the use of a targeted therapy like dasatinib based on gene expression pathways in select ovarian cancers,’ she said.

The results of the study are being presented on a poster at the 100th annual American Association for Cancer Research meeting in Denver on April 19, 2009. The study was funded by the Prudent Fund and the National Institutes of Health.

‘Our ultimate goal is to offer personalized therapy for women with ovarian cancer,’ said Angeles Secord, MD, a gynecologic oncologist at Duke and senior investigator on this study.

‘Hopefully in the future we will apply targeted therapies to individual patients and their cancers in order to augment response to treatment while minimizing toxic side effects.’

For this study, researchers examined four ovarian cancer cell lines, known as IGROV1, SKOV3, OVCAR3 and A2780. Three of the cell lines demonstrated high activation of SRC and one demonstrated lower SRC expression.

All were treated in lab dishes with various combinations of the chemotherapeutic agents dasatinib, carboplatin and paclitaxel.

‘We found that the addition of dasatinib to standard therapy in the three cell lines with significant SRC pathway deregulation – IGROV1, OVCAR3 and A2780 – enhanced the response of the cancer cells to therapy,’ Teoh said.

‘Conversely, in SKOV3, which has minimal SRC protein expression and pathway deregulation, we saw the least amount of anti-cancer activity when we added dasatinib.’

It’s possible that by blocking the SRC activity with the dasatinib, we are enhancing the effect of the other chemotherapeutic agents, Teoh said.

The results of this study support the further investigation of targeted biologic therapy using a SRC inhibitor in some ovarian cancers, she said. Currently a phase I trial of a combination of dasatinib, paclitaxel and carboplatin is available for women with advanced or recurrent ovarian, tubal and peritoneal cancers.

Dasatinib is a chemotherapeutic that is currently FDA-approved for use in leukemia. It is manufactured by Bristol-Myers Squibb and is sold under the brand name Sprycel. Bristol-Myers Squibb provided the dasatinib used in this study.

Other researchers involved in this study include Tina Ayeni, Jennifer Rubatt, Regina Whitaker, Holly Dressman and Andrew Berchuck.”

Source: Addition of Dasatinib to Standard Chemo Cocktail May Enhance Effect in Certain Ovarian Cancer, by Duke Medicine News and Communications, News, Health Library, DukeHealth.org, April 13, 2009.

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Endocyte Begins Phase II Clinical Trial of EC145 for Treatment of Women with Platinum Resistant Ovarian Cancer

Endocyte Inc. has announced the initiation of a randomized Phase II clinical study of the company’s investigational drug EC145 in women with platinum-resistant ovarian cancer. The phase II trial, also called the “PRECEDENT study,” will evaluate the efficacy and safety of EC145 when administered in combination with pegylated liposomal doxorubicin (PLD). …The PRECEDENT study will enroll 122 subjects and involve more than 50 clinical centers in the U.S., Canada, and Europe. … EC145 links a very potent anticancer drug to the vitamin folate, which is required for cell division. Rapidly dividing cancer cells over-express folate receptors to capture enough folate to support cell division. By combining a chemotherapy drug with folate, EC145 targets cancer cells while avoiding normal cells. This targeted approach is designed to provide treatment with more potent drugs with lower toxicity.”

″WEST LAFAYETTE, IN. – February 19, 2009 – Endocyte Inc. has announced the initiation of a randomized Phase II clinical study of the company’s investigational drug EC145 in women with platinumresistant ovarian cancer. The phase II trial, also called the “PRECEDENT study,” will evaluate the efficacy and safety of EC145 when administered in combination with pegylated liposomal doxorubicin (PLD).  PLD is widely used as a standard therapy for women with platinum-resistant ovarian cancer. The efficacy and safety of the combination of EC145/PLD  will be compared to treatment with PLD without EC145. Ovarian cancer is the fifth most common cancer among women in the United States and the leading cause of death due to cancer of the female reproductive system. The PRECEDENT study will enroll 122 subjects and involve more than 50 clinical centers in the U.S., Canada, and Europe. Trial details can be found at www.endocyte.com and http://www.clinicaltrials.gov.  EC145 links a very potent anticancer drug to the vitamin folate, which is required for cell division. Rapidly dividing cancer cells over-express folate receptors to capture enough folate to support cell division. By combining a chemotherapy drug with folate, EC145 targets cancer cells while avoiding normal cells. This targeted approach is designed to provide treatment with more potent drugs with lower toxicity.

  Advanced Ovarian Cancer - Imaging folate-receptors cancer cells using EC20 (folate-Tc99m). Source:  Endocyte

Advanced Ovarian Cancer - Imaging folate-receptors cancer cells using EC20 (folate-Tc99m). Source: Endocyte

In addition to EC145, patients in the PRECEDENT trial will also be treated with a new molecular imaging agent called EC20 developed by Endocyte. By targeting folate receptors, EC20 imaging agent allows clinicians to identify tumors that overexpress the folate receptor. Using EC20, doctors may be able to identify, in advance, those patients who will benefit from EC145 therapy. According to Dr. Wendel Naumann of the Blumenthal Cancer Center, Carolinas Medical Center and principal investigator for the PRECEDENT study, ‘Patients with advanced, platinum resistant, ovarian cancer are in need of therapy that does not result in significant toxicity. The earlier clinical studies of EC145 were encouraging because they indicated that clinicians could use EC20 to identify women whose tumors expressed the molecular target of EC145. Therapy with EC145 might benefit these patients without causing significant additional toxicity.’ ‘The start of the PRECEDENT study is another important validation of Endocyte’s promising DGS [Drug Guidance System] technology platform,” said Dr. Richard Messmann, Endocyte’s vice president for medical affairs. ‘This also represents an important milestone in Endocyte’s efforts to develop a range of new drugs and predictive medicine tools to treat cancer and other serious diseases in the years ahead. ‘

About Endocyte
Endocyte is a privately-held biotechnology company with headquarters in the Purdue Research Park of West Lafayette, IN. Based on the applications of Endocyte’s advanced proprietary Drug Guidance System (DGS), the Company is working to develop new drugs and diagnostic agents to treat many types of cancer and other serious diseases. The DGS platform makes it possible to use highly-potent drugs on extended and frequent dosing schedules and in combination with other drugs to maximize efficacy. The technology improves drug targeting and reduces the risk of side effects by combining drugs with ligands that are able to identify and attach to receptors found on tumor and other disease cells. Endocyte is currently conducting three separate Phase 2 clinical trials for its lead compound, EC145, together with EC20, a companion molecular imaging agent, for the treatment of ovarian cancer and non-small cell lung cancer. Other clinical-stage products in the Endocyte pipeline include: EC0225, a combination of two potent anticancer drugs; BMS493, a potent drug being developed in partnership with Bristol-Myers Squibb; EC17, a targeted immunotherapy agent; and EC0489, a targeted cancer drug. The Company also has multiple product candidates in pre-clinical stage development.  This press release contains “forward-looking statements” as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements are based on management’s current expectations and involve significant risks and uncertainties that may cause results to differ materially from those set forth in the statements. We undertake no obligation to publicly update any forwardlooking statement, whether as a result of new information, future events, or otherwise.

Contacts:
Vickey Buskirk, media relations, Endocyte Inc., (765) 463-7175 ext. 1117, vbuskirk@endocyte.com”

Quoted Source: ENDOCYTE BEGINS PHASE II CLINICAL TRIAL OF EC145 FOR TREATMENT OF WOMEN WITH OVARIAN CANCER, News Release, February 19, 2009 (PDF Document).

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