Sanofi on Wednesday said an experimental multiple sclerosis drug succeeded in a mid-stage trial, giving the company the confidence to bring the medicine into pivotal testing next year.
In a study of 129 patients with relapsing disease, the drug, called frexalimab, significantly reduced the number of “T1” brain lesions on an imaging scan — a sign of active inflammation — compared to a placebo. After 12 weeks of treatment, study volunteers receiving a low dose had a 79% reduction in brain lesions versus placebo, while those who got a high dose had an 89% reduction.
The drug also lowered the number of new or growing “T2” lesions, which indicate disease burden. After six months of treatment, no new T1 lesions were found in 96% of those who received a high dose of the drug.
The most common adverse events reported in the study were mild or moderate cases of COVID-19 and headaches. Sanofi said the drug was “well-tolerated” overall, and noted how 97% of trial participants continued to a second, open-label phase of the study. It didn’t provide additional details.
Sanofi plans to begin pivotal testing in 2024.
The results are an early sign of potential for a drug that Sanofi licensed from privately-held, New Hampshire-based biotechnology startup ImmuNext six years ago. The deal handed Sanofi rights to the medicine in exchange for up to $500 million in milestone payments.
Sanofi’s interest in frexalimab lies in how it works. An antibody, the drug is designed to block a signaling protein called CD40L that’s involved in the activation and function of a variety of immune cells. It’s meant to do so without lowering counts of white blood cells called lymphocytes, a side effect of other MS therapies that can lead to infections or other health problems.
In a statement, study investigator Gavin Giovannoni, a neurology professor at Queen Mary University of London, said the drug’s target is “pivotal in the pathogenesis of MS.”
“We are thrilled with the results achieved with frexalimab in just 3 months, which shows that CD40L inhibition rapidly controls MS disease activity without lymphocyte depletion,” he said in the statement.
Sanofi is exploring its use in several autoimmune conditions and, since signing the deal, has started Phase 2 trials in MS, lupus and Sjogren’s syndrome, according to a federal clinical trials database. The MS study is the first to report results. Initial findings from the Sjogren’s study could come later this year.
Frexalimab could soon become the second MS drug Sanofi has in late-stage testing. The other, a pill named tolebrutinib, was acquired in its 2020 buyout of Principia Biopharma. U.S. testing of that drug was stalled due to safety concerns, but the company still expects Phase 3 results either this year or early next.