Platinum agent promising as second-line prostate cancer therapy

May 15, 2007

Satraplatin, an investigational oral drug administered with prednisone, reduces the risk of disease progression in patients with advanced prostate cancer who have failed to respond to hormone treatment and chemotherapy by one-third.

Key Points

Orlando, FL-Satraplatin, an investigational oral drug administered with prednisone, reduces the risk of disease progression in patients with advanced prostate cancer who have failed to respond to hormone treatment and chemotherapy by one-third, researchers reported at the third annual Prostate Cancer Symposium here.

"Currently, there is no FDA-approved second line treatment for hormone-resistant prostate cancer. Docetaxel is an approved first-line agent. So we opened the Satraplatin and Prednisone Against Refractory Cancer (SPARC) trial in 2003 to evaluate satraplatin compared to placebo."

In the phase III SPARC trial, a cohort of 950 patients with advanced prostate cancer participated. The men were randomly assigned to receive prednisone with either satraplatin or placebo. Patients in the satraplatin arm had a 33% reduction in the risk of disease progression compared with patients in the placebo arm, Dr. Petrylak, the study's lead author, reported.

Improvement in progression-free survival observed among patients receiving satraplatin and prednisone increased over time. At 6 months, the disease did not progress among 30% of the patients on the satraplatin and prednisone regimen, whereas 17% of those in the placebo group did not progress. At 12 months, 16% of the satraplatin plus prednisone group did not have disease progression, compared to 7% of patients in the placebo group.

One-third lower progression risk

"We looked at progression-free survival as the primary endpoint. We found there is a one-third less chance of progression if they received satraplatin compared to those who received placebo," Dr. Petrylak told Urology Times. "There was acceptable toxicity; less than 5% of patients had grade 3 or 4 non-hematologic toxicities. The most common toxicities were myelosuppression, such as thrombocytopenia; neutropenia; and gastrointestinal, such as nausea, vomiting, or diarrhea, which were generally mild to moderate.

"We are excited about the preliminary findings. Before, we did not have options for second-line treatment for prostate cancer. We hope that this drug will be approved by the FDA and, if it is, we will have a second-line agent for this disease."

A new drug application for satraplatin was submitted to the FDA earlier this year.

Dean Bajorin, MD, of Memorial Sloan-Kettering Cancer Center in New York, called SPARC a well-designed comparison study of satraplatin versus placebo.

Dr. Petrylak is a consultant/adviser to GPC Biotech, and Dr. Bajorin has served as a consultant to the company.