Consolidation strategies in ovarian cancer: observations for future clinical trials

PURPOSE.: To describe the characteristics of a series of study populations of ovarian cancer patients with identical eligibility criteria in second or subsequent clinical remission (cCR) and to propose endpoint benchmarks for future consolidation studies. PATIENTS AND METHODS.: The patient populations consisted of those (1) untreated (U; observed until progression; n=35, (2) receiving imatinib (G; n=32), (3) receiving goserelin and bicalutamide (A; n=32), and (4) receiving vaccine (V; n=68; total=167). The endpoint of the combined analysis was progression-free survival in second remission (PFS 2). Patient characteristics were compared by chi-square test, and factors predicting PFS 2 evaluated in multivariate Cox model. RESULTS.: Groups were comparable for age, stage, grade, and debulking. Multivariate model to predict PFS 2 duration included histology, stage, optimal debulking, PFS 1 duration, and the type of intervention. As a benchmark for future studies, the median PFS 2 of the combined population of G, A, and U (removing V which had the most impact in prolonging PFS 2, n=68) was 11.3 months (95% CI: 10.4-12.5 months). The percent of patients with PFS 2>PFS 1 was 14/90 (16%). At 12 months, 43% remain progression-free. CONCLUSION.: Preliminary benchmarks for efficacy endpoints are suggested for future consolidation trials of patients in cCR. However, the suggested strategies will require validation in randomized trials and larger data sets.