The role of pentostatin in the treatment of T-cell malignancies: analysis of response rate in 145 patients according to disease subtype.

Abstract

To assess the results of treatment with the purine analog 2'deoxycoformycin (pentostatin [DCF]) in patients with postthymic T-cell malignancies. One hundred forty-five patients with postthymic T-cell malignancies were given DCF intravenously at 4 mg/m2/wk for the first 4 weeks and then every 2 weeks until maximal response; the last 30 patients received weekly injections until maximal response. The overall response rate was 32% (complete responses [CRs] plus partial responses [PRs]), with marked variation according to diagnosis. The best responses occurred in patients with Sézary syndrome (62%) and T-prolymphocytic leukemia (T-PLL) (45%), with CRs in three of 16 Sézary syndrome and five of 55 T-PLL patients. In contrast, no responses (NRs) were documented in 13 patients with other types of cutaneous T-cell lymphoma, including five mycosis fungoides. Two of five patients with large granular lymphocyte (LGL) leukemia had a CR and two of four with Sézary cell leukaemia had a PR. A low response rate was observed in 27 patients with peripheral T-non-Hodgkin's lymphoma (T-NHL) (19%) and in 25 with adult T-cell leukemia/lymphoma (ATLL) (12%). The latter included two CRs and one PR. Toxicity was low and DCF was generally well tolerated. No significant differences were observed when results were analyzed according to previous treatment. Disease subtype was the most important factor to influence results. We conclude that DCF is effective as a single agent in T-PLL, Sézary syndrome, and LGL leukemia, but has low activity in other T-cell disorders.