Satraplatin Shown To Significantly Reduce Risk Of Disease Progression In Advanced Hormone-Refractory Prostate Cancer Patients
NEW YORK - Daniel P. Petrylak, M.D. was a principal investigator of a study showcased at the Prostate Cancer Symposium of the American Society of Clinical Oncologists, on Feb. 23, 2007. The study, which involved nearly 1,000 patients with advanced prostate cancer, found that treatment with an investigational chemotherapy, called satraplatin, helps stop the growth of tumors.
“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,” said Dr. Petrylak, associate professor of medicine at Columbia University College of Physicians & Surgeons and Director of the Genitourinary Oncology Program at New York-Presbyterian Hospital/Columbia.
“The data 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 Taxotere®,” added Dr. Petrylak.
The trial, called SPARC (Satraplatin and Prednisone Against Refractory Cancer), 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.
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 hormone-refractory prostate cancer (HRPC).
Increase in prostate specific antigen (PSA) was not part of the progression endpoint. Progression-free survival (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 Taxotere® (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.
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.
About Satraplatin 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.
About Prostate Cancer 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.
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