Targeting CD38 with the monoclonal antibody daratumumab (Dara) is a widely used treatment in the setting of relapsed or refractory multiple myeloma (MM).1, 2, 3, 4, 5, 6 Therefore, Dara is currently approved, in combination with lenalidomide or bortezomib, for treatment of patients with MM who have received at least one prior line of treatment. This evidence concerns the gene CD38 and Miyoshi myopathy.