Mirum Pharmaceuticals Enters Into Definitive Agreement to Acquire Bluejay Therapeutics

New York – December 8, 2025 – Cooley advised Mirum Pharmaceuticals, a leading rare disease company, on its definitive agreement to acquire Bluejay Therapeutics, a privately held biotechnology company focused on viral and liver diseases. The transaction would add worldwide rights to brelovitug, a late-stage, fully human monoclonal antibody with Breakthrough Therapy and PRIME designations for chronic hepatitis delta virus (HDV), to Mirum’s portfolio of rare liver programs.

Under the terms of the definitive agreement, Mirum agreed to acquire all outstanding shares of Bluejay for $250 million in cash and $370 million in Mirum common stock, plus potential tiered sales-based milestone payments of up to $200 million in cash. The Mirum common stock issued to the Bluejay security holders at closing will be priced at $71.2085 per share.

Mirum also entered into a definitive agreement with a syndicate of existing and new healthcare investors for the sale of Mirum common stock and, to certain investors, in lieu of Mirum common stock, prefunded warrants, in a private placement. The private placement is expected to close concurrently with the acquisition and result in gross proceeds of approximately $200 million to Mirum. The Mirum common stock issued to the private placement investors at closing will be priced at $68.48 per share.

Lawyers Jason Kent, Kevin Cooper, Julia Kim, Nicholaus Johnson, Samuel Paullin, Amiti Rothstein, Rebeca Kinslow, Kathryn Benvenuti, Alexandria Ashour and Talya Whyte led the Cooley team advising Mirum.

Cooley previously advised Mirum on its $120 million Series A financing round in November 2018.

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