Sanofi Advances Frexalimab With New Phase 3 Study of Subcutaneous vs. IV Dosing in Multiple Sclerosis

Sanofi SA (SNY) announced an update on their ongoing clinical study.

Study Overview

Sanofi is launching a Phase 3 trial titled “A Randomized, Phase 3, Open-label Study to Investigate Pharmacokinetics, Safety, and Efficacy of Subcutaneous Compared to Intravenous Frexalimab in Adult Participants With Multiple Sclerosis.” The goal is to show that a simple under-the-skin (subcutaneous, SC) injection of frexalimab works at least as well as the current drip-based (intravenous, IV) version in adults with relapsing forms of multiple sclerosis. For investors, the study matters because easier dosing can support better patient uptake, stronger pricing power, and a more competitive profile versus other MS drugs.

Intervention/Treatment

The study tests frexalimab, an experimental MS treatment, given in two ways: as a solution injected under the skin and as an infusion into the vein. Both forms aim to control disease activity and reduce flare-ups in people with multiple sclerosis. Patients will also receive MRI contrast agents by IV to track changes in brain lesions during the trial.

Study Design

This is an interventional Phase 3 study in which participants are randomly assigned to either SC or IV frexalimab. Both groups are treated in parallel over the same period. The trial is open-label, so doctors and patients know which route of administration they receive. The main purpose is treatment: to compare how the two dosing methods move through the body, how safe they are, and how well they manage MS symptoms over roughly one year.

Study Timeline

The trial is listed as “not yet recruiting,” signaling Sanofi is preparing to enroll participants. The study was first submitted on December 23, 2025, marking the formal start of regulatory and site setup activities. The latest update on ClinicalTrials was posted on January 6, 2026, indicating the protocol and planning details are current. Primary and final completion dates have not yet been posted, but investors should expect initial readouts roughly one to two years after enrollment begins, in line with the 48-week treatment period and follow-up.

Market Implications

If frexalimab’s SC form proves non-inferior to IV in real-world MS patients, Sanofi could gain a more convenient product that fits outpatient and home-injection use, a clear advantage in a crowded MS market dominated by players such as Biogen, Roche, Novartis, and Merck KGaA. A positive SC profile would support better adherence and potentially higher market share against both infusion-based therapies and older injectables. In the near term, this update mainly signals ongoing investment and confidence in the frexalimab program rather than an immediate earnings driver. However, it reinforces Sanofi’s strategic push in neurology and may support sentiment for long-term growth, especially if investors view frexalimab as a future pillar in the company’s immunology and MS franchises. Competitive risk remains, as several rivals also pursue more convenient and high-efficacy options, but a successful SC conversion typically extends a product’s lifecycle and improves pricing flexibility.

The study is currently moving through its setup phase and remains active in planning, with further details and future updates available on the ClinicalTrials portal.

To learn more about SNY’s potential, visit the Sanofi SA drug pipeline page.