Oditrasertib, which blocks the inflammatory RIPK1 protein, earlier this year also failed a Phase II trial in amyotrophic lateral sclerosis, forcing the company to discontinue its development a few months later.
Sanofi is discontinuing a Phase II multiple sclerosis study of its investigational RIPK1 blocker oditrasertib after the candidate failed to meet its primary and key secondary endpoints, according to an SEC filing on Thursday by partner Denali Therapeutics.
Denali and Sanofi were evaluating oditrasertib in the mid-stage K2 study, a randomized, double-blinded and placebo-controlled trial that enrolled more than 170 patients with relapsing-remitting multiple sclerosis (MS), secondary progressive MS or primary progressive MS. The primary efficacy endpoint was oditrasertib’s effect on serum neurofilament light chain levels.
No specific details were provided in Denali’s SEC document, nor did the company identify which particular secondary outcomes oditrasertib missed. The California biotech also did not address oditrasertib’s safety profile.
Designed to be orally available, oditrasertib is an investigational inhibitor of the RIPK1 protein, which is a crucial signaling player in inflammatory and cell death pathways. In neurodegenerative diseases, RIPK1—along with other proteins from the same family—tends to be overactivated, leading to widespread inflammation and large-scale cell death in the brain. By targeting RIPK1, oditrasertib disrupts this pathological process, in turn preserving the integrity and function of the brain.
Despite a promising mechanism of action, however, oditrasertib has had a challenging clinical showing recently.
In April 2024, Sanofi announced plans to terminate a Phase II trial of oditrasertib in amyotrophic lateral sclerosis (ALS) after a disappointing mid-stage readout. A few months earlier, in February 2024, Sanofi and Denali announced that oditrasertib failed the Phase II HIMALAYA study in ALS, unable to significantly improve disease severity, as measured by the ALS Functional Rating Scale-Revised.
Developing effective therapies for MS has proven difficult. In September 2024, another Sanofi asset, the BTK inhibitor tolebrutinib, failed to significantly improve relapse rates in two Phase III studies. Tolebrutinib redeemed itself a few weeks later by significantly delaying disability onset in patients with non-relapsing secondary progressive MS in a third Phase III trial.
That same month, a study published in the peer-reviewed journal Neurology raised questions about the use of anti-CD20 antibodies in multiple sclerosis. According to its findings, there appear to be no significant difference in relapse or the progression of disability between patients who were given these therapies versus those who were untreated.
The study focused on primary progressive multiple sclerosis, for which the only approved anti-CD20 therapy is Roche’s Ocrevus (ocrelizumab). Other agents in the same drug class are also approved for relapsing forms of MS, including Novartis’ Kesimpta (ofatumumab) and TG Therapeutics’ Briumvi (ublituximab).
