MAJOR ACTIVITY OF CLADRIBINE IN PATIENTS WITH DE-NOVO B-CELL PROLYMPHOCYTIC LEUKEMIA

Purpose: De novo B-cell prolymphocytic leukemia (B-PLL) is a distinct clinicopathologic entity usually characterized by marked lymphocytosis , massive splenomegaly, an aggressive course, and refractoriness to th erapy. Cladribine (2-chlorodeoxyadenosine [2-CdA]; Ortho Biotech, Rari tan, NJ) is a newer purine analog with potent activity against indolen t lymphoproliferative disorders. Patients and Methods: We treated eigh t patients with cladribine 0.1 mg/kg/d for 7 days by continuous infusi on or 0.14 mg/kg/d over 2 hours for 5 days, every 28 to 35 days, for a median of three courses (range, two to five), There were five men and three women, with a median age of 62 years and a median pretreatment duration of 6 months; four patients were previously untreated. Results : All eight patients were assessable: five achieved ct complete respon se with a median response duration of 14 months (range, 1+ to 55+), an d three achieved a partial response with a median duration of 3 months (range, 1 to 3). Of four patients who achieved a complete response an d in whom a peripheral-blood immunophenotypic analysis was performed, two had no circulating B-PLL cells and one had no residual disease on Southern blot analysis. Myelosuppression and infection were the major toxicities: three patients developed grade 3 or 4 myelosuppression, fo ur had bacterial infections, and two had herpes tester infections. Con clusion: In this small study of patients with de nova B-PLL, cladribin e was an active agent that induced a high overall and complete respons e rate. These results require confirmation in larger numbers of B-PLL patients. (C) 1997 by American Society of Clinical Oncology.