Phase II study of alemtuzumab in chronic lymphoproliferative disorders.

Background: Pilot studies showed that alemtuzumab is active in lymphoproliferative disorders. The authors conducted a Phase II trial to evaluate the efficacy and safety of alemtuzumab in advanced or refractory chronic lymphoproliferative disorders.

Methods: Seventy-eight patients were enrolled. The most common diagnoses were chronic lymphocytic leukemia (n = 42 patients) and T-cell prolymphocytic leukemia (n = 18 patients). Before entering the study, the patients had received multiple therapies (median, three therapies) and the median time from diagnosis was 7 years. Alemtuzumab was given intravenously at doses of 3 mg, 10 mg, and 30 mg on 3 consecutive days, after which 30 mg was administered 3 times a week. Patients were treated for 4-12 weeks depending on disease response. All patients received prophylactic trimethoprim/sulfamethoxazole and valacyclovir.

Results: The overall response rate was 35%, the complete response (CR) rate was 13%, and the partial response (PR) rate was 22%. The median duration of response was 18 months for patients achieving a CR and 7 months for patients achieving a PR. The median duration of survival was 25 months for patients who had a response and 12 months for the entire population. Normalization of the lymphocyte count was observed in 84% of patients and resolution of bone marrow involvement was observed in 49% of patients. The most common infusion-related adverse events were fever, rigors, skin rash, nausea, and dyspnea. These were most common during the first week of therapy. Hematologic toxicity was comprised of long-lasting lymphocytopenia and transient neutropenia and thrombocytopenia. Thirty-six patients (46%) experienced at least one episode of fever or infection.

Conclusions: Alemtuzumab has a high response rate in patients with chronic lymphoproliferative disorders.