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 <70 years. CONCLUSION: This postmarketing surveillance confirmed the safety and effectiveness of mogamulizumab for the treatment of patients with r/r ATL, including elderly patients, in clinical practice.