5-Year Survival in Patients With Relapsed or Refractory Chronic Lymphocytic Leukemia in a Randomized, Phase III Trial of Fludarabine Plus Cyclophosphamide With or Without Oblimersen

Purpose A randomized trial of oblimersen plus fludarabine/cyclophosphamide (OBL-FC; n = 120) versus FC (n = 121) was conducted in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). The primary end point was met: the complete response (CR) rate, defined as complete or nodular partial response, was significantly greater with OBL-FC than with FC (17% v 7%; P = .025). Among patients with CR, response duration was significantly longer with OBL-FC than with FC (median not reached; > 36 months v 22 months; P = .03). Maximum benefit with OBL-FC, including a four-fold increase in CR rate and a survival benefit with 3 years of follow-up (hazard ratio, 0.53; P = .05), was observed in patients with fludarabine-sensitive disease. We evaluated long-term survival and poststudy CLL therapy among all randomly assigned patients. Methods Poststudy CLL treatment information was collected. Patients were observed for survival for up to 5 years from the date of random assignment. Results Poststudy CLL treatment was balanced between arms. Intent-to-treat analysis of 5-year survival showed no significant between-treatment difference (hazard ratio, 0.87; P = .34). Among the greater than 40% of patients with complete or partial remission, a significant 5-year survival benefit was observed with OBL-FC (hazard ratio, 0.60; P = .038). Among patients with fludarabine-sensitive disease who had previously demonstrated maximum benefit with OBL-FC, the previously observed survival benefit improved: a 50% reduction in the risk of death was observed (P = .004). Conclusion In relapsed/refractory CLL, OBL combined with FC offers patients who achieve complete or partial remission, as well as those who have fludarabine-sensitive disease, a significant survival benefit.