Selinexor in Patients from Argentina with Multiple Myeloma Treated with Multiple Prior Therapies: A Case Series

BACKGROUND Numerous treatment options are available for patients with multiple myeloma (MM). Because of the course of the disease, most patients will experience serial relapse or the MM will become refractory to most of these treatments, leaving patients with few or no treatment options over time. Selinexor, a treatment with a novel mechanism of action, is an oral selective inhibitor of nuclear export (SINE) compound that blocks exportin 1, the major nuclear exporter of tumor suppressor proteins. CASE REPORT In this case series, we report on treatment with the weekly oral administration of selinexor combined with bortezomib and dexamethasone (XVd) in 3 patients from Argentina who were heavily treated (5-7 prior therapies) for MM that relapsed or was refractory to each previous treatment. Two patients had the high-risk cytogenetic abnormality del(17p). All 3 patients experienced efficacy with XVd reaching a best response of partial response or very good partial response. These responses were consistent with those of patients from the BOSTON study who were treated with XVd but were less heavily pretreated (1-3 prior therapies) and had a shorter median time since diagnosis of MM (7 years vs 3.7 years). The 3 patients experienced adverse events (AEs) that included nausea, thrombocytopenia, asthenia, and fatigue, which were similar to the most commonly reported AEs associated with selinexor treatment. CONCLUSIONS With its oral administration, novel mechanism of action, and responses in heavily pretreated patients, selinexor may help to address an important clinical need in the treatment of patients with relapsed/refractory MM.