Satraplatin, a chemotherapy drug has recently been tested in 950 patients with Hormone Refractory Prostate Cancer Patients and found to have significant improvement in Progression-Free Survival.
A report from Columbia University on Phase III trial on Satraplatin has shown:
* Highly Statistically Significant Results for Improvement in Progression-Free Survival
* Progression-Free Survival Results Consistent Irrespective of Prior Chemotherapy Treatment, including TaxotereŽ
* Satraplatin was Well Tolerated with Myelosuppression the Most Commonly Observed Toxicity
Satraplatin, an investigational drug, is a member of the platinum family of compounds. Over the past two decades, platinum-based drugs have become a critical part of modern chemotherapy treatments and are used to treat a wide variety of cancers. Unlike the platinum drugs currently on the market, all of which require intravenous administration, Satraplatin is an orally bioavailable compound and is given as capsules that patients can take at home.
Prostate cancer is the most common cancer among men in the U.S. and Europe. Approximately 219,000 men in the U.S. are expected to be diagnosed with the disease in 2007 and over 27,000 men are expected to die from the disease. In the European Union, over 200,000 new cases are expected to be diagnosed, and over 60,000 patients are expected to die each year.
Since the incidence of prostate cancer increases with age, the aging of the overall population is expected to further increase the number of prostate cancer patients.
Most patients diagnosed with prostate cancer initially receive surgery or radiation therapy, and some of these patients are cured. For many others, though, the disease recurs. At this point, the recurrent disease is treated with hormone therapy, and most patients initially respond well to this treatment. Eventually, however, the tumor cells become resistant to the hormones - or "hormone-refractory" - and the tumor again progresses. Increasingly, chemotherapy is being used as an effective first-line treatment for hormone-refractory prostate cancer. However, it is not a cure, and so this is creating a need for effective therapeutic options for these patients once they have progressed.
The trial is evaluating Satraplatin plus prednisone versus placebo plus prednisone in 950 patients with hormone-refractory prostate cancer (HRPC) who have failed prior chemotherapy. All analyses of Progression-free survival (PFS) being presented was conducted on an intent-to-treat basis.
Progression-free survival (PFS) results for the double-blind, randomized Satraplatin Phase 3 registrational trial, the SPARC trial (Satraplatin and Prednisone Against Refractory Cancer)
The study data show that Satraplatin significantly reduces the risk of disease progression in these patients using the protocol-specified log-rank test. The hazard ratio of 0.6 (95% CI: 0.5-0.7, p<0.00001), which was first reported in September 2006, adjusted for nine pre-specified prognostic factors. Using a more conservative analysis, which adjusted only for the three pre-specified stratification factors, the hazard ratio is 0.67 (95% CI: 0.57-0.77, p=0.0000003).
These hazard ratio numbers correspond to a reduction in relative risk of disease progression of 40% and 33%, respectively. Both analyses are being presented today in Orlando.
In accordance with the recommendation of the independent Data Monitoring Board for the SPARC trial, patients who have not progressed continue to be treated and all patients will be followed for overall survival. Overall survival data are expected to be available later this year. GPC Biotech recently completed the New Drug Application (NDA) submission for Satraplatin to the U.S. Food and Drug Administration (FDA). Pharmion expects to complete the Marketing Authorization Application (MAA) for Europe in the second quarter of 2007.
Daniel Petrylak, M.D., Associate Professor of Medicine at Columbia University College of Physicians & Surgeons, Director of the Genitourinary Oncology Program at New York-Presbyterian Hospital/Columbia, and a Principal Investigator in the SPARC trial, said: "As there are currently no approved therapies for patients with hormone-refractory prostate cancer whose disease has already failed on one chemotherapy regimen, Satraplatin has the potential to address a mounting area of unmet medical need. The data I am presenting today show statistically significant results in progression-free survival in favor of those patients treated with Satraplatin. These results are consistent no matter what the prior chemotherapy treatment, including TaxotereŽ."
All disease progression events were adjudicated by an independent expert review committee of medical oncologists and radiologists. The vast majority of progression events were based on radiological progressions and pain progressions. Pain associated with bone metastases is the dominant cause of morbidity in patients with metastatic HRPC. Increase in prostate specific antigen (PSA) was not part of the progression endpoint. PFS at the median demonstrated a 14% improvement in patients who received Satraplatin plus prednisone (11.1 weeks) compared to patients who received prednisone plus placebo (9.7 weeks). The improvement seen in PFS by patients treated with Satraplatin increased over time. PFS at the 75th percentile showed an 81% improvement for patients in the Satraplatin arm ( 34.6 weeks) versus patients in the placebo arm (19.1 weeks). At six months, 30% of patients in the Satraplatin arm had not progressed, compared to 17% of patients in the control arm. At twelve months, 16% of patients who received Satraplatin had not progressed, compared to 7% of patients in the control arm.
The median number of cycles was four for the Satraplatin group compared to two for the control group. Nearly 40% of patients treated with Satraplatin received five or more cycles of treatment compared to approximately 20% of patients in the control arm.
The improvement in PFS in the Satraplatin arm was not affected by the type of prior chemotherapy; importantly, the improvement was similar for patients who had received prior TaxotereŽ (docetaxel), as well as those who received other types of chemotherapy treatments. Fifty-one percent of patients in the trial were previously treated with Taxotere. The hazard ratio for patients in the SPARC trial who were previously treated with Taxotere was 0.67 (95% CI: 0.54-0.83; p=0.0006, adjusted for the pre-specified stratification factors) and therefore numerically equivalent to the entire study population.
Safety findings were consistent with previous clinical studies involving Satraplatin. The reported adverse reactions were mostly mild to moderate in severity. The most common adverse reactions consisted of myelosuppression (bone marrow functions): Twenty-one percent of patients in the Satraplatin arm experienced grade 3 or 4 thrombocytopenia; 14 percent had leucopenia and 21 percent had neutropenia. Eight percent of patients in the Satraplatin arm experienced grade 3 or 4 gastrointestinal toxicities, including nausea, vomiting, diarrhea and constipation. Five percent or less of patients in the Satraplatin arm experienced grade 3 or 4 fatigue, grade 3 or 4 infections and pulmonary/respiratory grade 3 or 4 toxicities.
"We are delighted with the strong detailed results presented today from the Satraplatin SPARC Phase 3 trial," said Bernd R. Seizinger, M.D., Ph.D ., Chief Executive Officer of GPC Biotech. "Moving forward, we plan to work closely with the FDA regarding our application for marketing approval of Satraplatin in the U.S. We also are continuing to aggressively build our marketing and sales organization in the U.S. to prepare for a potential launch of Satraplatin later this year."
"We have been very pleased with the response of the prostate cancer treatment community to the SPARC data and believe that Satraplatin will become a very important treatment option for men with HRPC," said Patrick J. Mahaffy, President and Chief Executive Officer of Pharmion Corporation. "We are currently preparing our regulatory submission and expect to file a marketing authorization application for Satraplatin in the EU by the end of the second quarter."
The SPARC trial is a double-blinded, randomized, placebo-controlled multinational Phase 3 trial assessing Satraplatin plus prednisone as a second-line chemotherapy treatment for patients with HRPC. A total of 950 patients were accrued to the trial at approximately 170 clinical sites in sixteen countries on four continents. In addition to the results presented today, the companies expect that more data from the SPARC trial will be presented at future upcoming major medical conferences.
Please note: The scientific information discussed in this press release related to Satraplatin is investigative. Satraplatin has not yet been approved by the FDA in the U.S., the EMEA in Europe or any other regulatory authority and no conclusions can or should be drawn regarding its safety or effectiveness. Only the relevant regulatory authorities can determine whether Satraplatin is safe and effective for the use(s) being investigated.
TaxotereŽ (docetaxel) is a registered trademark of Aventis Pharma S.A.
For Further information contact: GPC Biotech at www.gpc-biotech.com.