Mirum Pharmaceuticals announced an acquisition of Bluejay Therapeutics for roughly $620 million in cash and stock to secure brelovitug, a late‑stage monoclonal antibody with Phase II data showing potent antiviral activity in chronic hepatitis D virus (HDV). Mirum said the deal includes additional contingent milestone payments and positions brelovitug for a potential 2027 BLA submission and commercial launch. Bluejay’s Phase II results reportedly demonstrated 100% HDV RNA response and liver‑enzyme improvements; a global Phase III AZURE program is ongoing with topline data expected in the second half of next year. Mirum framed the acquisition as strategic—expanding its rare‑liver disease portfolio and leveraging existing commercial channels. The transaction underscores continued M&A in rare and niche antiviral programs where single‑asset companies command premiums. Mirum also announced a concurrent private placement to bolster balance sheet resources for clinical and commercial work.