Mirum Pharmaceuticals agreed to acquire Bluejay Therapeutics for roughly $620 million in cash and stock to secure brelovitug, a monoclonal antibody in late‑stage testing for chronic hepatitis D (HDV). The companies said the purchase combines Mirum’s rare‑liver commercial experience with Bluejay’s clinical momentum and aims to position brelovitug for a 2027 regulatory push. Brelovitug produced 100% HDV RNA response in a recent Phase 2 readout and is enrolled in a Phase 3 program expected to report pivotal data next year, according to Bluejay’s filings and Mirum’s release. Mirum CEO Chris Peetz framed the deal as a strategic fit for the company’s liver‑disease franchise and announced an accompanying private placement to fund development. The transaction includes upfront cash and stock plus potential milestones; Bluejay shareholders can receive up to $200 million in sales‑based payments. The deal accelerates consolidation in rare liver disease where late‑stage assets can change commercial positioning quickly.