Apellis hits setback in ALS trial after pair of pegcetacoplan approvals

Developing meds for amyotrophic lateral sclerosis (ALS) is challenging under the best of circumstances. Now, Apellis Pharmaceuticals has run into a setback for its candidate.

Friday, Mizuho Securities broke the news of a “clinical setback for pegcetacoplan,” Apellis’ C3 inhibitor that's already approved by the FDA to treat paroxysmal nocturnal hemoglobinuria (PNH) and geographic atrophy (GA).

Specifically, Apellis and its partner Sobi ended the open-label extension arm of the phase 2 study Meridian in ALS. The move came after a data monitoring committee decided the drug wasn’t meeting the mark in the wake of newly available data, Apellis confirmed in an emailed statement.

Apellis’ 250-patient Meridian study kicked off in September of 2020 and dosed patients over 52 weeks before the initiation of the open-label extension portion of the trial. The main portion of the trial has already wrapped and Apellis aims to share by the middle of the year whether the drug met its primary endpoint by helping boost function and survival in ALS patients.

“A decision on next steps for the program will be made following the planned analysis of the full data,” Apellis said in its email.  

Elsewhere on the ALS front, Biogen’s Ionis-partnered antisense medicine, tofersen, is up for an FDA accelerated approval decision this week. The drug, which tackles a subset of ALS patients, flunked a midstage trial but posted encouraging follow-up biomarker data that seemed to sway an FDA advisory committee of the drug’s potential.

Further, Mizuho said Apellis' setback could be good news for Amylyx's recently approved Relyvrio, which was the first ALS treatment that showed a significant slowing in both disease progression and functional decline, as well as extended survival, in a randomized clinical trial. 

ALS prospects from the likes of Biogen, Cytokinetics, Alexion Pharmaceuticals and Biohaven have all run up against clinical hurdles in the past two years.

As for Apellis’ pegcetacoplan, the drug has already banked two approvals in as many years.

Back in May 2021, the C3 inhibitor muscled in on turf held by Alexion’s Soliris in PNH, where analysts predicted the drug could score $513 million by 2026.

Separately, pegcetacoplan made history under the moniker Syfovre as the first drug approved for GA last February. Geographic atrophy is an advanced stage of age-related macular degeneration that forms one of the leading causes of blindness.

Editor's note: This story has been updated to clarify that the original period for Apellis' Meridian trial ran for 52 weeks.