Sanofi-aventis updated about the results from the phase-3 trial, Tropic, that demonstrated the investigational drug cabazitaxel plus prednisone/prednisolone, significantly improved overall survival, versus an active chemotherapy combination of mitoxantrone plus prednisone/prednisolone, in patients with metastatic hormone-refractory (castration-resistant) prostate cancer whose disease progressed following treatment with docetaxel-based chemotherapy.

“It is impressive to see the updated results continue to demonstrate an improvement in overall survival compared with that achieved with a standard chemotherapy regimen,” said Marc Cluzel, executive vice-president, Research & Development, sanofi-aventis. “These are encouraging results in a difficult-to-treat stage of prostate cancer.”

Updated results of the primary end point (overall survival) – to be presented at the 2010 American Society of Clinical Oncology (ASCO) Annual Meeting on June 6 – will show that the combination of cabazitaxel and prednisone/prednisolone significantly reduced the risk of death by 28% [HR=0.72 (95% CI: 0.61-0.84); P<0.0001] with an improvement in the median overall survival of 15.1 months vs. 12.7 months in the mitoxantrone combination arm.

The most frequent grade 3/4 hematological adverse events with cabazitaxel were neutropenia (81.7%) assessed by laboratory values, leukopenia (68.2%), anemia (10.5%), and febrile neutropenia (7.5%); the most frequent grade 3/4 non-hematological adverse events were diarrhea (6.2%), fatigue (4.9%), and asthenia (4.6%). Discontinuation of treatment due to adverse events occurred in 18.3% of patients in the cabazitaxel arm and 8.4% of patients in the mitoxantrone arm. Most frequent treatment-emergent adverse events leading to discontinuation in the cabazitaxel arm were neutropenia (2.4%), hematuria (1.3%), diarrhea (1.1%) and fatigue (1.1%). Grade 3/4 peripheral neuropathy occurred in 0.5% of patients in the cabazitaxel arm vs. 0.3% in the mitoxantrone arm. Deaths due to adverse events were 4.9% in the cabazitaxel arm (predominantly due to neutropenia and its complications) vs. 1.9% in the mitoxantrone arm.

“Providing solutions that have a major impact on patients with cancer, such as metastatic castration-resistant prostate cancer, is the driving force behind everything we do,” said Debasish Roychowdhury, senior vice president, Global Oncology, sanofi-aventis. “The development of cabazitaxel is one of many investigational compounds we hope to present to the cancer community in the months and years to come.”

The Tropic study results were chosen by the ASCO Committee to be presented on July 16-17 and July 23-24 at the Best of ASCO sessions in San Francisco, CA and Boston, MA; these meetings are held to provide wider access to cutting-edge science presented at the annual meeting.

Cabazitaxel is an investigational compound that has been shown to be active in cell lines refractory to chemotherapies.