RANDOMIZED COMPARISON OF PENTOSTATIN VERSUS INTERFERON ALFA-2A IN PREVIOUSLY UNTREATED PATIENTS WITH HAIRY-CELL LEUKEMIA - AN INTERGROUP STUDY

Purpose: Therapy of hairy cell leukemia has markedly improved. Interfe ron alfa-2a and pentostatin are active agents. The National Cancer Ins titute organized an intergroup trial to compare these agents prospecti vely in untreated patients. Methods: Patients were randomized to recei ve either interferon alfa-2a (3 x 10(6) U subcutaneously three times p er week) or pentostatin (4 mg/m(2) intravenously every 2 weeks). Patie nts who did not respond to initial treatment were crossed over. Result s: Of 356 patients on study, 313 were eligible. Among interferon patie nts, 17 of 159 (11%) achieved a confirmed complete remission and 60 of 159 (38%) had a confirmed complete or partial remission. Among pentos tatin patients, 117 of 154 (76%) achieved a confirmed complete remissi on and 121 of 154 (79%) had a confirmed complete or partial remission. Additional patients achieved criteria for complete remission, but lac ked con firmatory follow-up evaluation. Response rates were significan tly higher (P < .0001) and relapse-free survival was significantly lon ger with pentostatin than interferon (P < .0001). The median follow-up duration is 57 months (range, 19 to 82). Myelosuppression was more fr equent with pentostatin (P = .013). A multivariate logistic regression analysis of the confirmed complete remissions on pentostatin showed t he following factors to be im portant for achieving a complete remissi on: high hemoglobin level (two-tailed P = .024), young age (P = .0085) , and no or little splenomegaly (P = .0029). Conclusion: Both agents w ere well tolerated. Pentostatin higher response rates, and the respons es were durable. Patient age and clinical status had an impact on outc ome with pentostatin. Pentostatin is effective therapy for hairy cell leukemia. J Clin Oncol 13:974-982. (C) 1995 by American Society of Cli nical Oncology.