Mirum Pharmaceuticals agreed to acquire Bluejay Therapeutics for $620 million in cash and stock to secure brelovitug, a monoclonal antibody in late‑stage development for chronic hepatitis D (HDV). The deal includes potential milestone payments and follows positive Phase 2 signals showing virologic responses. Bluejay has been enrolling a Phase 3 program expected to report top‑line data next year; Mirum said it intends to pursue submission and commercialization with a 2027 timeline under consideration. The transaction pairs Mirum’s rare liver disease commercial experience with Bluejay’s clinical asset and ongoing trials. Terms include a $250 million cash component and $370 million in Mirum stock, with up to $200 million in sales‑based milestones. Company statements framed the deal as strategic for Mirum’s hepatic rare‑disease franchise.