Selinexor was initially approved by the US Food and Drug Administration (FDA) in combination with dexamethasone for the treatment of adult patients with relapsed or refractory MM who have received at least four prior therapies and whose disease is refractory to at least 2 PIs, at least 2 IMiDs, and an anti-CD38 mAb–penta-refractory MM. This evidence concerns the gene CD38 and Miyoshi myopathy.