Phase 4 linvoseltamab BCMA×CD3 bispecific with prophylactic tocilizumab IL-6R blockade

Regeneron Pharmaceuticals is running this Phase 4, single-arm, multicenter outpatient study testing whether giving tocilizumab prophylactically before the first linvoseltamab dose can reduce cytokine release syndrome (CRS) risk in heavily pretreated relapsed/refractory multiple myeloma. Linvoseltamab is a BCMA×CD3 bispecific antibody that redirects T cells to kill BCMA-expressing plasma cells, while tocilizumab (an IL‑6 receptor monoclonal antibody) aims to blunt IL‑6–driven inflammatory cascades that contribute to CRS. The core design is pragmatic: deliver prophylactic tocilizumab, then administer linvoseltamab per protocol, tracking CRS incidence/severity, need for hospitalization, and use of supportive medications like corticosteroids or rescue tocilizumab. Eligible participants have received at least 4 prior lines including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 antibody. The commercial/scientific angle is operational—expanding bispecific therapy into safer outpatient delivery by preempting CRS—where today’s care for late-line RRMM is sequential therapies including BCMA- and GPRC5D-directed agents (bispecifics or CAR-T when feasible) plus supportive care, often requiring step-up dosing with close monitoring.