Frexalimab
An investigational treatment for Multiple Sclerosis.
The same compound appears under different names depending on the context. Here is how to identify Frexalimab wherever you encounter it, plus the key facts at a glance.
- Generic name
- Frexalimab
- Development code
- SAR441344
- Drug class
- Monoclonal antibody (anti-CD40L)
- Manufacturer
- Sanofi
- How it's taken
- In the Phase 2 MS trial, frexalimab was given either as 1,200 mg by IV infusion every 4 weeks or as 300 mg injected under the skin every 2 weeks.
A novel immunomodulator that stops the activation signals between immune cells without killing them. In Phase 2, the high dose reduced new brain lesions by 89%, and 2 Phase 3 trials have finished enrolling.
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How Frexalimab works
Frexalimab blocks CD40L, a molecule that acts as a 'go' signal for both acute immune responses (causing relapses) and chronic brain inflammation (causing disability). By blocking this signal, the drug reduces both sudden immune attacks and slow, ongoing brain damage.
Mechanism: Fc-engineered anti-CD40L monoclonal antibody that blocks the CD40/CD40L costimulatory pathway needed for T and B cell activation, without depleting lymphocytes
Side effects and safety
In Phase 2 trials, frexalimab demonstrated a favorable safety profile with mild to moderate adverse events. The Phase 3 side effect profile has not yet been published, but early data suggest fewer side effects than many current treatments.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Frexalimab
In the Phase 2 MS trial, frexalimab was given either as 1,200 mg by IV infusion every 4 weeks or as 300 mg injected under the skin every 2 weeks. The Phase 3 trials FREXALT and FREVIVA together enrolled about 2,600 people.
Clinical trial results
In a 12-week Phase 2 trial of 129 people with relapsing MS, the high dose of frexalimab (1,200 mg IV) reduced new gadolinium-enhancing brain lesions by 89% versus placebo, and the lower dose (300 mg under the skin) by 79%. The Phase 3 FREXALT trial (NCT06141473) compares frexalimab with teriflunomide in 1,655 people with relapsing MS, and FREVIVA (NCT06141486) compares it with placebo in 943 people with non-relapsing secondary progressive MS. Both started in December 2023, have finished enrolling, and are expected to report results in 2027 and 2028.
Main registered trial: NCT06141473 on ClinicalTrials.gov. Check it for the current status, sites and contacts before asking about enrollment.
Development history
Frexalimab was developed by Sanofi under exclusive license from ImmuNext. It is a second-generation anti-CD40L antibody. Both Phase 3 MS trials started in December 2023, and Sanofi is also testing it in kidney transplantation.
Explore Multiple Sclerosis trials
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Common questions about Frexalimab
▸What is Frexalimab?
A novel immunomodulator that stops the activation signals between immune cells without killing them. In Phase 2, the high dose reduced new brain lesions by 89%, and 2 Phase 3 trials have finished enrolling.
▸How does Frexalimab work?
Frexalimab blocks CD40L, a molecule that acts as a 'go' signal for both acute immune responses (causing relapses) and chronic brain inflammation (causing disability). By blocking this signal, the drug reduces both sudden immune attacks and slow, ongoing brain damage.
▸What are the side effects of Frexalimab?
In Phase 2 trials, frexalimab demonstrated a favorable safety profile with mild to moderate adverse events. The Phase 3 side effect profile has not yet been published, but early data suggest fewer side effects than many current treatments.
▸How is Frexalimab taken?
In the Phase 2 MS trial, frexalimab was given either as 1,200 mg by IV infusion every 4 weeks or as 300 mg injected under the skin every 2 weeks. The Phase 3 trials FREXALT and FREVIVA together enrolled about 2,600 people.
▸Is Frexalimab FDA approved?
Frexalimab is currently in phase 3 clinical trials for Multiple Sclerosis. It has not yet received FDA approval.
▸How is frexalimab different from other MS antibody therapies?
Most MS antibody therapies (like ocrelizumab and ofatumumab) work by depleting immune cells, killing B cells to reduce the immune attack on the nervous system. Frexalimab takes a fundamentally different approach by blocking CD40L, a costimulatory signal that immune cells need to become activated. Without this activation signal, T cells and B cells remain in a resting state rather than being destroyed. This means frexalimab modulates immunity without depleting the immune system, which could preserve the ability to fight infections and respond to vaccines.
▸What did the Phase 2 trial show?
In the 12-week Phase 2 trial of 129 people, the high dose of frexalimab reduced new gadolinium-enhancing brain lesions by 89% compared with placebo, and the lower dose by 79%. These results led Sanofi to start Phase 3 trials.
▸What are the FREXALT and FREVIVA trials?
FREXALT is a Phase 3 trial comparing frexalimab with teriflunomide in 1,655 people with relapsing MS. FREVIVA compares frexalimab with placebo in 943 people with non-relapsing secondary progressive MS. Both have finished enrolling, and results are expected around 2027 (FREXALT) and 2028 (FREVIVA).
▸Why is the CD40L pathway important in MS?
The CD40/CD40L interaction is a costimulatory signal that activates both T cells and B cells and helps drive autoimmune responses. In MS, blocking this pathway could in theory address both acute relapses and chronic inflammation inside the brain. Whether it does so will be shown by the Phase 3 trials.
▸Is frexalimab available to patients?
No. Frexalimab is still in Phase 3 trials and has not been submitted for FDA approval. Both Phase 3 MS trials have finished enrolling. Patients interested in future studies can check ClinicalTrials.gov and talk with their neurologist.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- Sanofi · 2024-02-15. Phase 2 data published in NEJM show potential of frexalimab. https://www.sanofi.com/en/media-room/press-releases/2024/2024-02-15-13-00-00-2829933
- ClinicalTrials.gov. FREXALT: frexalimab vs teriflunomide in relapsing MS. https://clinicaltrials.gov/study/NCT06141473
- ClinicalTrials.gov. FREVIVA: frexalimab in non-relapsing secondary progressive MS. https://clinicaltrials.gov/study/NCT06141486