After spending the year angling for a new approval in multiple sclerosis, Sanofi's stockings may hang empty this holiday season—at least when it comes to tolebrutinib in non-relapsing secondary progressive MS (nrSPMS).
The FDA doesn't intend to make a decision on the company's filing for tolebrutinib in nrSPMS by Dec. 28 as previously planned, Sanofi said in a Dec. 15 press release.
Back in March, Sanofi picked up an FDA priority review for the filing and touted an expected approval decision by Sept. 28. But, as that date neared in the fall, the drugmaker disclosed a three-month delay due to its submission of "additional analyses" during the review, which constituted a "major" amendment to the application by the FDA's standards.
Now, with the second consecutive delay in the books, Sanofi expects to hear new guidance from the FDA by the end of March, the company said in its release.
But the delay wasn't the only piece of bad news for Sanofi and its tolebrutinib ambitions Monday. In addition, the company disclosed that the phase 3 Perseus study missed the mark in patients with primary progressive MS (PPMS). That study assessed the ability of the BTK inhibitor to delay time to six-month composite confirmed disability progression versus placebo.
Sanofi won't seek regulatory approval for the drug in PPMS, the company said Monday.
So continues the rocky path for the drug, which Sanofi picked up in its $3.7 billion buyout of Principia Biopharma back in 2021. The following year, the FDA put a group of late-stage studies under a partial clinical hold so it could review reports of drug-induced liver injury.
Two years on from that, Sanofi reported that the drug failed two out of three late-stage studies in MS but that it still planned to seek an approval in nrSPMS thanks to its clinical win in that indication. The mixed bag of results ultimately dented the med's therapeutic scope, and Sanofi removed tolebrutinib's use in relapsing MS from its pipeline early this year.
In secondary progressive MS, patients typically have been diagnosed with relapsing MS but have stopped having relapses and instead experience "disability accumulation," Sanofi explained in its press release. Despite advances in MS care, unmet need remains in this treatment setting as options are limited, according to the company.