PILOT-STUDY OF ALL-TRANS-RETINOIC ACID AS POSTREMISSION THERAPY IN PATIENTS WITH ACUTE PROMYELOCYTIC LEUKEMIA

Chemotherapy may decrease relapses of acute promyelocytic leukemia (AP L) following induction with all-trans retinoic acid (ATRA), however th e optimal timing of these two modalities remains to be determined. We treated eight patients with morphologic evidence of Apt. with intensiv e induction chemotherapy followed by ATRA (45 mg/m(2)/d for 10 weeks). All eight patients achieved a complete remission following chemothera py. After a median follow-up of 29.0 months, seven patients remain in complete remission; one patient relapsed at 26.9 months. RT-PCR analys is for the PML/RAR alpha rearrangement was performed to monitor patien ts for evidence of minimal residual disease. Both of tile patients wit h persistence of this rearrangement after induction chemotherapy conve rted to negative following ATRA. Toxicity of ATRA given in the postrem ission setting was mild and consisted of headache, dry skin, and eleva tions of triglycerides and transaminases. No patient developed evidenc e of the retinoic acid syndrome. The administration of ATRA after inte nsive induction chemotherapy is associated with durable remissions and minimal toxicity in patients with APL. Disappearance of the PML/RAR a lpha rearrangement after ATRA suggests that ATRA is effective against minimal residual disease.