Sanofi and clinical-stage biopharmaceutical company Inhibrx, Inc. announced a definitive agreement on 23 January 2024 under which Sanofi will acquire Inhibrx following the separation of its non-INBRX-101 assets into a newly established company, New Inhibrx. The transaction is valued at approximately $1.7 billion in equity value and will add INBRX-101, an investigational treatment for alpha-1 antitrypsin deficiency (AATD), to Sanofi’s rare disease development portfolio.

INBRX-101 targets alpha-1 antitrypsin deficiency

INBRX-101 is a human recombinant alpha-1 antitrypsin (AAT) protein being developed as an augmentation therapy for people with AATD, a rare inherited condition characterised by insufficient levels of AAT. The disease primarily affects the lungs and can lead to progressive tissue damage.

The candidate is designed to increase serum AAT levels, with the potential advantage of monthly rather than weekly dosing. This could reduce treatment frequency for patients, although its clinical benefit and safety still require regulatory assessment.

Transaction structure and shareholder consideration

Under the agreement, Sanofi will acquire all outstanding shares of Inhibrx for $30 per share in cash, representing an equity value of approximately $1.7 billion on a fully diluted basis. Shareholders will also receive:

• one non-transferable contingent value right (CVR) per share, providing for an additional $5 cash payment if a specified regulatory milestone is achieved
• 0.25 shares in New Inhibrx for each Inhibrx share held

The potential CVR payment would represent approximately $296 million in additional consideration if the relevant milestone is achieved. Sanofi will also assume responsibility for Inhibrx’s outstanding third-party debt.

New Inhibrx will retain the assets not related to INBRX-101, including the company’s immuno-oncology pipeline. It is to receive $200 million in cash at distribution, while Sanofi will retain an 8% equity interest in the new company.

Expected completion in the second quarter of 2024

The transaction was unanimously approved by the boards of directors of both companies. Completion remained subject to the spin-off of the non-INBRX-101 assets and other customary closing conditions. Sanofi expected the transaction to close in the second quarter of 2024 and planned to finance the acquisition using available cash resources.

The agreement supports Sanofi’s strategy of expanding its rare disease portfolio, building on its established activities in rare diseases, immunology and inflammation. For patients with AATD, INBRX-101 represents a potential additional treatment option, subject to successful clinical development and regulatory approval.