Boulevard Bio emerged from stealth mode with $65 million in launch financing from Deerfield Management, debuting multi-specific antibodies aimed at B cell-driven autoimmune diseases. The company is led by CEO Mahesh Karande and is advancing three multi-specific antibody programs designed to deliver durable disease control while reducing treatment burden. Boulevard’s lead asset, BLVD101, is a bispecific antibody targeting BAFF and APRIL—cytokines involved in B cell survival and activation. The company is initially evaluating BLVD101 in IgA nephropathy, with interim Phase 1 information from healthy volunteers suggesting a potential quarterly dosing interval. Deerfield’s internal build-to-spinout model is central to the story: the programs were developed through its 3DC platform before spinning out as an independent biotech, a path that may reduce early-stage costs and accelerate clinical readiness.