This study investigated the antitumor activity of alemtuzumab (Campath 1-H) with regard to response rate, time to progression, overall survival and adverse events in patients with human T-cell lymphotrophic virus-1 (HTLV-1)-associated adult T-cell leukemia/ lymphoma (ATL). In a single institution non-randomized open-label phase II trial, 24 patients with chronic (n=2), acute (n=13) and lymphomatous (n=9) ATL were treated with intravenous alemtuzumab 30 mg three times weekly for a maximum of 12 weeks. Patients received antimicrobial prophylaxis from the initiation of treatment continuing for a minimum of 2 months after treatment, or until the peripheral blood CD4+ T-cells were ≥ 200 cells/μL. Tumor responses were assessed at the end of 4, 8, and 12 weeks. All patients were evaluable for toxicity and one patient was not evaluable for response due to early withdrawal. The overall objective response rate was 10 out of 23 patients (95% CI: 23 to 66%). Based on the 10 patients who responded, median time to response was 1.1 months (range, 1.0 to 3.0 months). The median response duration was 3.9 months. Median progression free survival of patients with chronic subtype was 2.0 months, 1.0 month for lymphomatous subtype and 2.4 months for acute subtype. Median time to treatment failure was 1.7 months. At data cut-off, (April 24, 2008), 6 (25%) patients were alive. Overall median survival was 5.9 months. Median overall survival by subtypes was 3.9 months for chronic, 4.8 months for lymphomatous, and 7.6 months for acute. Median survival for all responders from on study date was 8.4 months. Clinical benefit was observed both in responders and in patients with stable disease. The most common adverse events were related to infusion and were generally grade 1 or 2, occurring mainly in the first week of alemtuzumab administration. All patients developed CMV antigenemia; however, only 3 (12.5%) were symptomatic. Grade 3 or 4 infections were reported in 6 (25%) patients. Median time to recovery of ALC to >200 cells/μL was 1.9 months.

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