Royalty Pharma Drops $525M for Royalties and Milestones on Sanofi-Licensed MS Therapy

M&A_iStock, Tippapatt

Pictured: Businessmen shaking hands after closing a deal/iStock, Tippapatt

Royalty Pharma on Thursday announced that it will acquire royalties and milestones on ImmuNext’s frexalimab, a first-in-class anti-CD40 monoclonal antibody that has been licensed to Sanofi for Phase III development in multiple sclerosis.

According to the terms of the deal, the New York-based biotech will pay ImmuNext approximately $525 million in cash, plus estimated transaction costs.

In return, Royalty will receive 100% of annual worldwide net royalties that ImmuNext would have received under its licensing deal with Sanofi, up to $2 billion. Beyond this threshold, Royalty will share a “minority” of the royalties with ImmuNext’s shareholders. The New York-based biotech will also be entitled to “substantial potential milestone payments” from Sanofi.

The companies expect to close the deal this month, pending regulatory and antitrust clearances and other customary closing conditions.

Royalty CEO Pablo Legorreta said in a statement that the agreement with ImmuNext “will expand our attractive and growing development-stage portfolio” and add a next-generation immunology candidate to its pipeline.

Designed to block the CD40/CD40L pathway, frexalimab is an investigational monoclonal antibody that has first-in-class potential for multiple sclerosis (MS). Under healthy circumstances, the CD40/CD40L pathway is involved in the activation and function of the adaptive and innate immune systems. Frexalimab’s inhibitory mechanism of action could temper the underlying hyperactive autoimmune response in MS.

In May 2023, Sanofi reported Phase II data for frexalimab, showing that the investigational antibody could significantly lower disease activity in patients with relapsing MS. At week 12, patients in the high-dose group saw an 89% drop in new gadolinium-enhancing T1-lesions, while counterparts in the low-dose group demonstrated a 79% decrease.

Due to frexalimab’s strong potential, Sanofi in December 2023 named it as one of its 12 pipeline assets with blockbuster potential, with potential peak sales of $5.4 billion. The pharma has already begun its Phase III assessment of frexalimab, aiming to enroll 1,400 MS patients and compare the antibody against teriflunomide.

“Frexalimab has the potential to achieve high efficacy without the chronic depletion of the immune system commonly associated with currently available MS therapies,” Legorreta said, adding that its promising mid-stage data, plus its potential in other immune conditions, position frexalimab as a “potentially transformative therapy for patients.”

Frexalimab has had its fair share of stumbles, too. In its recent first-quarter business report, Sanofi revealed that it had discontinued the antibody’s development in Sjögren’s syndrome due to weak Phase II results.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at or

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