Mirum Pharma's $268M Gambit to Conquer Rare and Liver Diseases

FOSTER CITY, CA – December 19, 2025 – Mirum Pharmaceuticals is making a significant strategic move to expand its dominance in specialized medicine, securing approximately $268.5 million in new capital to fund its proposed acquisition of Bluejay Therapeutics. The financing was solidified with a new agreement for a $68.5 million private placement with institutional investor TCGX, supplementing a $200 million placement announced earlier this month.

This infusion of capital is earmarked to bring Bluejay, a private biotechnology company focused on viral and liver diseases, into the Mirum fold. The acquisition and both private placements are expected to close concurrently in the first quarter of 2026, contingent on regulatory approval and other standard closing conditions. The move signals Mirum's aggressive strategy to not only deepen its existing rare disease portfolio but also to make a major entry into the larger market for severe liver conditions.

A Strategic Play for a Late-Stage Prize

The centerpiece of the Bluejay acquisition is its lead drug candidate, brelovitug (BJT-778). This asset is a high-potency, fully human monoclonal antibody currently in a Phase 3 clinical program for treating chronic hepatitis D (HDV), widely considered the most severe form of viral hepatitis. The potential of brelovitug is underscored by its multiple regulatory accolades; it has received Breakthrough Therapy designation from the U.S. Food and Drug Administration (FDA) and both Orphan and PRIME designations from the European Medicines Agency (EMA).

Brelovitug works by targeting the surface antigen of the hepatitis B virus (anti-HBsAg), aiming to neutralize and clear both hepatitis B (HBV) and HDV virions from the body. Phase 2 studies have already shown promising results, with participants demonstrating a 100% HDV RNA response and improvements in liver enzyme levels, all with a favorable safety profile. With top-line data from its Phase 3 AZURE study expected in the second half of 2026, Mirum could be on track for a Biologics License Application (BLA) submission and a potential commercial launch in 2027, representing a near-term, high-impact revenue opportunity.

Beyond its lead candidate, Bluejay Therapeutics brings a broader pipeline targeting chronic hepatitis B. This includes Cavrotolimod, a toll-like receptor 9 (TLR9) agonist, and BJT-628, a liver-targeted transcript inhibitor. These assets are being developed for use in combination therapies with the goal of achieving a functional cure for chronic HBV, a significant unmet need globally. The acquisition effectively hands Mirum a well-developed, late-stage pipeline in a therapeutic area adjacent to its core expertise.

The Financial Firepower Behind the Deal

To execute this ambitious acquisition, Mirum has leaned on private capital, a common strategy for growth-stage biotech companies looking to fund major strategic moves without unsettling public markets. The latest $68.5 million investment comes from TCGX, a prominent investment firm specializing in both private and public biotech companies. TCGX, which recently closed its third fund with $1.3 billion in capital commitments, is known for making substantial, long-term investments in companies with transformative potential.

Their participation, alongside the earlier $200 million placement, serves as a powerful endorsement of Mirum's strategy and the perceived value of the Bluejay acquisition. This combined $268.5 million in gross proceeds will provide Mirum with ample runway to not only complete the acquisition but also to fund the intensive clinical development and commercial launch activities for brelovitug. As of its last reporting period in September 2025, Mirum held approximately $370 million in cash and equivalents. While the company has demonstrated impressive revenue growth of over 53% in the last year, it has yet to achieve profitability. This substantial capital raise enables the firm to pursue a transformative acquisition without taking on excessive debt or depleting its operational cash reserves.

Wall Street's Bullish Reception

The market and analyst community have responded with strong optimism to Mirum's strategic maneuvering. The company's stock (NASDAQ: MIRM) has been a standout performer, recently hitting an all-time high of $78.55 and boasting a gain of approximately 64% over the past year. This momentum reflects growing investor confidence in Mirum's existing commercial portfolio—which includes LIVMARLI, CHOLBAM, and CTEXLI—and its expanding pipeline.

Following the acquisition announcement, several investment banks reiterated their confidence by raising their price targets for Mirum's stock. Analysts at Leerink Partners reportedly praised the deal as a well-aligned use of capital, noting that Bluejay's late-stage liver disease assets fall directly within Mirum's operational 'sweet spot.' The firm subsequently adjusted its price target for Mirum to $100. Similarly, Citizens raised its target to a lofty $140, expressing high confidence in the brelovitug asset, while Raymond James increased its target to $110. H.C. Wainwright also reiterated its Buy rating on the stock. This chorus of positive analyst sentiment suggests that Wall Street views the acquisition not as a risky gamble, but as a calculated and value-accretive step forward for the company.

Navigating the New Regulatory Gauntlet

The final hurdle for the transaction is regulatory clearance, a process that has become increasingly rigorous in the biopharmaceutical sector. In late 2023, the Federal Trade Commission (FTC) and the Department of Justice (DOJ) finalized new merger guidelines aimed at preventing anticompetitive consolidation in healthcare. These agencies are now applying heightened scrutiny to deals, examining their potential impact on market concentration, future innovation, and the elimination of potential competitors.

Regulators will likely assess whether Mirum's acquisition of Bluejay could stifle competition in the development of treatments for rare and viral liver diseases. High-profile challenges, such as the FTC's initial opposition to Amgen's $27.8 billion takeover of Horizon Therapeutics, have shown that even deals with seemingly little direct product overlap can face intense review. While Mirum's acquisition is on a smaller scale, it will be evaluated against this new, stricter framework. The successful and timely closing of the deal in the first quarter of 2026 hinges on convincing regulators that the combination will foster, rather than hinder, innovation and patient access in these critical disease areas.