Phase II study of alemtuzumab in combination with pentostatin in patients with T-cell neoplasms

Purpose: To examine the efficacy and safety of the combination of alemtuzumab and pentostatin in patients with T-cell neoplasms. Patients and Methods: We treated 24 patients with a variety of T-cell leukemias and lymphomas with a combination of alemtuzumab 30 mg intravenously (IV) three times weekly for up to 3 months and pentostatin 4 mg/m² IV weekly for 4 weeks followed by alternate weekly administration for up to 6 months. Prophylactic antibiotics including antiviral, antifungal, and antibacterial agents were administered during the treatment and for 2 months after its completion. Results: The median age of patients was 57 years (range, 21 to 79 years). Eight patients were previously untreated, and 16 had a median of two prior therapies (range, one to six regimens). Thirteen patients responded to treatment (11 complete responses [CRs] and two partial responses), for an overall response rate of 54%. The median response duration was 19.5 months. Monoclonal T-cell receptor chain gene rearrangements were detected by polymerase chain reaction in bone marrow of 20 of 22 evaluable patients and became negative in five of seven evaluable patients in CR. Opportunistic infections caused by pathogens associated with severe T-cell dysfunction were common. Conclusion: The combination of alemtuzumab and pentostatin is feasible and effective in T-cell neoplasms. Although infections, including cytomegalovirus reactivation, are a concern, they may be minimized with adequate prophylactic antibiotic therapy.