Phase II Study of Pentostatin in Advanced T-Cell Lymphoid Malignancies: Update of an M. D. Anderson Cancer Center Series

BACKGROUND. The goal of the current study was to assess the toxicity, safety, and efficacy of pentostatin in patients with T-cell lymphoid malignancies. METHODS. Patients were eligible if they had biopsy-proven T-cell lymphoma or leukemia and failure to respond to previous therapy or an expected complete response rate to conventional therapy of < 20%. Pentostatin was administered at an initial dose of 3.75 or 5.0 mg/m² by intravenous bolus daily over a consecutive 3-day period every 3 weeks. RESULTS. Forty-two of 44 patients enrolled in the study were evaluable. The median age of the patients was 62 years (range, 38-86 years). Patients received a median of 3 previous therapies (range, 0-10 previous therapies). Of these patients, 32 (76%) had mycosis fungoides/Sézary syndrome and 10 patients (24%) had other T-cell leukemias or lymphomas. The overall response rate was 54.8% (complete remission, 6 patients [14.3%]; partial remission, 17 patients [40.5%]). Durable responses were observed mainly in patients with Sézary syndrome or peripheral T-cell lymphoma. The median follow-up period for surviving patients was 20 months (range, 1-83+ months). The median duration of response was 4.3 months (range, 1-61 months). The most common toxicities were neutropenia, nausea, and CD4 suppression. A transient early 'flare' of disease was observed in some responders. CONCLUSIONS. At these doses, pentostatin was reasonably well tolerated and is an effective drug for the treatment of T-cell lymphomas.