The FDA has granted accelerated approval to selinexor (Xpovio, Karyopharm Therapeutics) in combination with dexamethasone for the treatment of adults with relapsed refractory multiple myeloma (RRMM). The medication is indicated for patients who have had at least four prior therapies and whose disease is resistant to several other treatment forms, including at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody.
Multiple myeloma, or plasma cell myeloma, begins in the plasma cells. Abnormal plasma cells build up in the bone marrow, forming tumors in many bones of the body. When more antibodies are produced, the blood can thicken and prevent the bone marrow from making enough healthy blood cells.
Efficacy was evaluated by treating 83 patients with Xpovio in combination with dexamethasone. At the study’s end, the overall response rate was measured at 25.3%. The median time to first response was four weeks, with a range of one to ten weeks. The median duration of response was 3.8 months.
Common side effects of taking Xpovio combined with dexamethasone included leukopenia, neutropenia, thrombocytopenia, and anemia. Patients also reported vomiting, nausea, fatigue, diarrhea, fever, decreased appetite and weight, constipation, upper respiratory tract infections, and hyponatremia.
Females of reproductive age and males with a female partner of reproductive potential should be advised to use effective contraception during treatment with Xpovio. Women who are pregnant or breastfeeding should not take Xpovio as it could harm the developing fetus or newborn baby.
Xpovio in combination with dexamethasone received an accelerated approval and fast track and orphan drug designations.
Source: FDA, July 3, 2019