Phase III double-blind placebo-controlled study of farnesyl transferase inhibitor R115777 in patients with refractory advanced colorectal cancer

Abstract

Purpose: To determine whether R115777 improves survival in patients with refractory advanced colorectal cancer (CRC) in a multicenter, double-blind, prospective randomized study.

Patients and methods: Three hundred sixty-eight patients were randomly assigned to R115777 (300 mg twice daily) orally for 21 days every 28 days or placebo in a 2:1 ratio. All patients received best supportive care. The primary end point was overall survival; secondary end points were progression free survival, tumor response, toxicity, and quality of life.

Results: The two treatment groups were well balanced for baseline demographics, including previous chemotherapy for advanced CRC. The median overall survival for R115777 was 174 days (95% CI, 157 to 198 days), and 185 days (95% CI, 158 to 238 days) for those patients receiving placebo (P =.376). One patient achieved a partial response in the R115777 arm. Stable disease (> 3 months) was observed in 24.3% patients in the R115777 group compared to 12.8% in the placebo arm. This did not translate into a statistically significant increase in progression-free survival. Overall, treatment was well tolerated. There was an increased incidence of reversible myelosuppression (neutropenia, thrombocytopenia), rash, and grade 1 to 2 diarrhea in the R115777 arm. There was no statistically significant difference in quality of life between arms.

Conclusion: Single agent R115777, given at this dose and schedule, has an acceptable toxicity profile, but does not improve overall survival compared to best supportive care alone in refractory advanced CRC.