Sanofi’s multiple sclerosis drug prospects include two proverbial shots on goal. With the first one stalled by a clinical hold, Sanofi is welcoming positive clinical data for a second one, results the pharmaceutical giant say support plans to advance to pivotal testing.
The experimental drug, frexalimab, was tested in a Phase 2 study enrolling 129 patients with the relapsing form of MS. The main goal was to measure the reduction in brain lesions characteristic of the disease after 12 weeks of treatment. Sanofi reported reductions of 89% in the high dose group and 79% in the low-dose group, both of those arms compared with a placebo. The results were presented Wednesday during the Consortium of Multiple Sclerosis Centers annual meeting in Aurora, Colorado.
MS is an immune-mediated disorder in which certain immune cells attack myelin, the protective sheath covering nerve fibers. Frexalimab is an antibody intended to block the CD40/CD40L pathway needed for immune cell activation and function. The drug accomplishes this without depleting lymphocytes, a type of white blood cell.
Frexalimab was initially developed by Lebanon, New Hampshire-based ImmuNext based on research from the Geisel School of Medicine at Dartmouth. In 2017, Sanofi licensed global rights to the antibody, which was in preclinical development at the time. Financial details of the deal were scant, but the companies said ImmuNext could receive up to $500 million in milestone payments. In addition to MS, frexalimab has reached Phase 2 testing in Sjogren’s syndrome and lupus.
Sanofi’s first shot on goal in MS was tolebrutinib, a small molecule that blocks Bruton’s tyrosine kinase. This enzyme regulates the growth and survival of B cells, an immune cell that contributes to the progression of MS. Sanofi acquired tolebrutinib as part of its $3.7 billion acquisition of Principia Biopharma in 2020. The key feature of the drug was its ability to penetrate into the central nervous system to provide its therapeutic effect. But last June, the FDA placed a clinical hold on a Phase 3 test of the drug in MS after reports of liver injury in some study participants. That hold remains in place.
The Phase 2 test of frexalimab is ongoing. After week 12, patients in the placebo group were switched onto the study drug. This open label portion of the study will evaluate the reduction in brain lesions after 12 weeks of treatment. So far, the drug has been well tolerated by patients. The most common adverse events reported in any of the frexalimab treatment groups were Covid-19 infections (a frequent problem since the start of the pandemic) and headache. Sanofi plans to start the Phase 3 test of the drug in 2024.
“Building on our 20 years of research and development in multiple sclerosis, we are committed to growing our robust pipeline of MS therapies by exploring multiple treatment approaches with unique [mechanisms of action] that have the potential to slow or halt disability, which remains one of the greatest unmet medical needs in multiple sclerosis today,” Erik Wallström, Sanofi’s global head of neurology development, said in a prepared statement.