The U.S. Food and Drug Administration (FDA) has approved Abecma (idecabtagene vicleucel) to treat relapsed or refractory multiple myeloma.

Idecabtagene vicleucel is a B-cell maturation antigen (BCMA)-directed chimeric antigen receptor (CAR) T cell immunotherapy given as a single infusion for the treatment of adult patients with multiple myeloma after four or more prior lines of therapy, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody.  The single infusion is created by collecting the patient’s own T-cells and genetically modified them to include a new gene that facilitates the targeting and killing of BCMA-positive myeloma cells.

The approval of idecabtagene vicleucel was largely based on the pivotal Phase II KarMMa trial in which patients with relapsed or refractory multiple myeloma who had received at least three prior lines of therapy, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 antibody, were given the CAR-T cell therapy. 

In the study, the overall response rate (ORR) for the efficacy evaluable population (n=100) was 72%, and 28% achieved a stringent complete response (sCR).  Of the 28 patients who achieved sCR, approximately 65% had remission lasting at least 12 months.

While effective, the newly approved therapy comes with a Box Warning for cytokine release syndrome (CRS), neurologic toxicities, hemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS), and prolonged cytopenia. 

In the KarMMa trial, CRS of any grade occurred in 85% of patients using the Lee grading system and 9% of patient had a Grade >3 CRS. Neurologic toxicities of any grade occurred in 28% of patients, including Grade ≥3 events in 4% of patients. Hemophagocytic lymphohistiocytosis/macrophage activation syndrome occurred in 4% of patients. 

Other common adverse events included infections, fatigue, musculoskeletal pain, hypogammaglobulinemia, diarrhea, upper respiratory tract infection, nausea, viral infections, encephalopathy, edema, pyrexia, cough, headache, and decreased appetite. 

The FDA is requiring that hospitals and the associated clinics that dispense the drug be specially certified and that the staff involved in the prescribing, dispensing or administering of idecabtagene vicleucel be trained to recognize and manage CRS and nervous system toxicities as well as other side effects of idecabtagene vicleucel.

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