High remission rate in T-cell prolymphocytic leukemia with CAMPATH-1H

T-cell prolymphocytic leukemia (T-PLL) is a chemotherapy-resistant malignan cy with a median survival of 7.5 months. Preliminary results indicated a hi gh remission induction rate with the human CD52 antibody, CAMPATH-1H. This study reports results in 39 patients with T-PLL treated with CAMPATH-1H bet ween March 1993 and May 2000. All but 2 patients had received prior therapy with a variety of agents, including 30 with pentostatin; none achieved com plete remission (CR). CAMPATH-1H (30 mg) was administered intravenously 3 t imes weekly until maximal response. The overall response rate was 76% with 60% CR and 16% partial remission (PR). These responses were durable with a median disease-free interval of 7 months (range, 4-45 months). Survival was significantly prolonged in patients achieving CR compared to PR or no resp onse (NR), including one patient who survived 54 months. Nine patients rema in alive up to 29 months after completing therapy. Seven patients received high-dose therapy with autologous stem cell support, 3 of whom remain alive in CR 5, 7, and 15 months after autograft. Stem cell harvests in these pat ients were uncontaminated with T-PLL cells as demonstrated by dual-color fl ow cytometry and polymerase chain reaction Four patients had allogeneic ste m cell transplants, 3 from siblings and 1 from a matched unrelated donor. T wo had nonmyeloablative conditioning. Three are alive in CR up to 24 months after allograft. The conclusion is that CAMPATH-1H is an effective therapy in T-PLL, producing remissions in more than two thirds of patients. The us e of stem cell transplantation to consolidate responses merits further stud y. (C) 2001 by The American Society of Hematology.