MANAGEMENT OF ACUTE PROMYELOCYTIC LEUKEMIA RELAPSE IN THE ATRA ERA

Background and Objective. The use of all-trans retinoic acid (ATRA) ha s changed the natural course of acute promyelocytic leukemia (APL), in creasing the percentage of lasting complete remissions. However, manag ement of the few relapses remains undefined. The purpose of the presen t study was to evaluate the different behavior of APL patients relapse d after induction chemotherapy which had or had not included ATRA. Des ign and Methods. We retrospectively studied 8 patients (3 male and 5 f emale) who had relapsed after a clinical and molecular complete remiss ion (CR). Five patients relapsed after conventional chemotherapy inclu ding antracyclines, without ATRA which was not available at the onset (group A), 3 relapsed after induction treatment according to AIDA prot ocol (idarubicin + ATRA) (group B). Seven patients had both molecular and clinical relapses, 1 (group B) had only a molecular relapse. The m edian first CR duration was 33 months (range 8-63). To induce a second CR all patients were treated with ATRA 45 mg/m(2)/day given orally un til CR, combined with mitoxantrone 6 mg/m2/day for 6 days and cytarabi ne 1 g/m(2)/day for 6 days. Results. Seven out of 8 patients (87.5%) a chieved second CR, 1 (group A) did not respond and died within two mon ths. Second CR duration was 21, 43+, 56+, 62+ months in group A and 5, 10,12+ (with molecular relapse) months in group B. Therefore, only on e patient relapsed in group A, while all the group B patients relapsed . Interpretation and Conclusions. ATRA combined with chemotherapy is a n effective approach to treating APL relapse. It produces a high incid ence of second CR with an acceptable toxicity. The duration of the sec ond CR seems, however, to be longer in patients never treated with ATR A before than in patients who relapsed after the AIDA protocol. Theref ore, it might be appropriate to adopt more aggressive protocols in thi s latter subset of patients. (C) 1998 Ferrata Storti Foundation.