Brexucabtagene autoleucel, sold under the brand name Tecartus, is a cell-based gene therapy medication for the treatment of mantle cell lymphoma (MCL) in adults. The most common side effects include serious infections, low blood cell counts and a weakened immune system. Brexucabtagene autoleucel is a chimeric antigen receptor T cell therapy and is the first cell-based gene therapy approved by the U.S. Food and Drug Administration (FDA) for the treatment of mantle cell lymphoma.