Safety and effectiveness of mogamulizumab in relapsed or refractory adult T‐cell leukemia‐lymphoma

Objective This prospective, observational, postmarketing surveillance was conducted to evaluate the safety and effectiveness of mogamulizumab, an anti‐CC chemokine receptor 4 (CCR4) monoclonal antibody, in patients with CCR4‐positive, relapsed or refractory (r/r) adult T‐cell leukemia‐lymphoma (ATL) in Japan. Method All patients were scheduled to receive intravenous infusions of mogamulizumab 1.0 mg/kg once weekly for 8 weeks, alone or in combination with other modalities. Results In the safety analysis population comprising 572 patients, mogamulizumab therapy was started between May 29, 2012, and April 30, 2013, and adverse drug reactions (ADRs) were reported in 73.4% (38.6% serious cases) of patients. The most common ADRs were skin disorders (33.2% [10.8% serious cases]), infusion‐related reactions (30.1% [4.7% serious cases]), and infections (22.0% [14.7% serious cases]). In the effectiveness analysis population comprising 523 patients, the best overall response rate and the response rate at the end of therapy were 57.9% and 42.0%, respectively. The median overall survival was 5.5 months. Safety and effectiveness results were similar between patients aged ≥70 and