What does the drug do?

Pegcetacoplan is an investigational medication developed by Apellis Pharmaceuticals that inhibits the activity of a protein called C3, which is involved in a specific immune response called the complement system. Incorrect activation of the complement system can cause inflammation and damage to healthy motor neurons. C3 protein levels have been found to be increased at motor end plates (the junction between nerves and muscles) in those with MND. Pegcetacoplan is designed to block the action of the C3 protein and reduce inflammation which might help to slow disease progression in those with MND.

This drug has already been successful in several trials for a rare blood disorder so a phase 1 trial for it’s use in MND was not needed, as pegcetacoplan has already been found to be safe and well-tolerated.

Trial Outcome

The open-label period of the trial of pegcetacoplan was ended earlier than planned. This decision was made following analysis of unblinded data, made by an independent data monitoring committee. The committee recommended not continuing treatment. This was not based on any safety concerns.

Topline results showed that, while the treatment was found to be safe and well tolerated, the drug did not meet the primary or secondary endpoints of the trial which suggests that it did not have any clinical benefit for people with MND. Apellis have made the decision to discontinue the development of pegcetacoplan for ALS. 

Clinical Trials

Phase 2 - MERIDIAN

The phase 2 trial to assess the safety and efficacy of pegcetacoplan in MND, called MERIDIAN, is taking place at sites across the U.S, Australia and Europe, including two sites in the UK. This trial aims to recruit 228 participants and has two stages, each one lasting for a year. The first stage involves the participants being randomly assigned to receive either a placebo or pegcetacoplan for a year. The second stage of the trial will allow all participants to be treated with pegcetacoplan for a year. You can find out more about the trial here.

Latest News


Dosing began in participants. 


May- Topline results were announced that pegcetacoplan showed no clinical benefit for MND and development for ALS is being discontinued.


April- The open label of the trial was ended early.

Last updated: 30/05/2023