T-cell prolymphocytic leukemia (T-PLL) is a chemotherapy-resistant malignancy 
with a median survival of 7.5 months. Preliminary results indicated a high 
remission induction rate with the human CD52 antibody, CAMPATH-1H. This study 
reports results in 39 patients with T-PLL treated with CAMPATH-1H between March 
1993 and May 2000. All but 2 patients had received prior therapy with a variety 
of agents, including 30 with pentostatin; none achieved complete remission (CR). 
CAMPATH-1H (30 mg) was administered intravenously 3 times 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 response (NR), including one patient 
who survived 54 months. Nine patients remain 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 patients were uncontaminated with T-PLL 
cells as demonstrated by dual-color flow cytometry and polymerase chain 
reaction. Four patients had allogeneic stem cell transplants, 3 from siblings 
and 1 from a matched unrelated donor. Two 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 use of stem cell transplantation to consolidate 
responses merits further study.