Alemtuzumab maintenance may safely prolong chemotherapy-free intervals in chronic lymphocytic leukemia

Abstract

This prospective, single-arm study utilized alemtuzumab as a single agent in a novel maintenance schedule in previously treated chronic lymphocytic leukemia patients with the goal of delaying progression of disease and requirement for chemotherapy. In previously treated CLL patients who had achieved stable disease or better, the following schedule of subcutaneous alemtuzumab was administered: a dose escalation in the first week (3, 10 and 30 mg), followed by 7 weeks of 30 mg alemtuzumab once weekly, 16 weeks of 30 mg once every 2 weeks, followed by once every 3 weeks for 24 weeks. Thus, the entire duration of the planned treatment was 48 weeks. A total of 12 patients were enrolled 11 of which had at least one marker of poor prognosis (unmutated, Zap 70+, CD38+, del11q and del17p). The median chemotherapy-free interval was 13 months, and the median time to disease progression was 10 months. Three patients achieved a CR, one achieved nPR, one had a PR, five failed and two had shown a beneficial response but because of recurrent ITP had to stop alemtuzumab. In six of the 10 patients with previously relapsed disease, the chemotherapy-free interval was longer than their prior chemotherapy-free period. One patient had a reactivation of CMV antigenemia, and another had a bacterial pneumonia. There were no grade 3 or 4 toxicities. Alemtuzumab used in a maintenance schedule is a potentially safe and useful tool in delaying disease progression and chemotherapy-free intervals in previously treated CLL patients.