Objective: Despite the improvement in progression-free and overall survival in patients with advanced ovarian cancer associated with platinum-taxane chemotherapy, strategies are needed to prevent the greater than 70% recurrence rate.
Method: The Southwest Oncology Group (SWOG) initiated a phase III intergroup trial of alpha-interferon (IFNalpha-26, Schering-Plough, Kenilworth, NJ) in weekly doses of 50 x 10(6) IU (for 6 doses) versus observation only in patients with no pathological evidence of residual disease at second-look surgery in 1988.
Results: Patient accrual was extremely slow and the trial was permanently closed in 1999 by the SWOG Data and Safety Monitoring Committee with 74 registered patients. Of these patients, 70 were evaluable for progression-free and overall survival. There was no significant difference between the two study arms in relation to median progression-free survival (P = 0.56). The median survival duration associated with intraperitoneal alpha-interferon had not been reached versus 87 months on the observation arm. In general, intraperitoneal alpha-interferon was well tolerated. There were no treatment-related deaths or grade 4 adverse events. Although no efficacy conclusions can be drawn from this prematurely closed trial, it should be noted that 57% of the patients on the observation arm recurred and all died, whereas 63% recurred and only 43% died on the intraperitoneal alpha-interferon arm.
Conclusion: Although this was a negative study, there should continue to be interest in the use of biological therapy to improve survival of patients in complete remission following primary chemotherapy.