Amylyx Pharmaceuticals has completed participant enrolment in the Phase III PHOENIX clinical trial of AMX0035 (sodium phenylbutyrate and taurursodiol [also known as ursodoxicoltaurine]) in amyotrophic lateral sclerosis (ALS) patients.

The randomised, 48-week, placebo-controlled, international Phase III clinical trial has been designed for assessing the safety and efficacy of AMX0035 in ALS patients.

A total of 664 participants with ALS have been enrolled in the trial, spanning over 65 sites across the US and Europe.

Most of the participants are members of the NEALS or TRICALS consortia.

In the trial, participants are randomised 3:2 to receive either AMX0035 or a placebo for a period of 48 weeks.

After completion of the 48-week trial, European participants will have the option to enrol in an open label extension (OLE) phase.

All the participants will receive AMX0035 during the OLE phase, and its efficacy and safety will continue to be evaluated.

A joint Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) total score progression evaluation over a period of 48 weeks, adjusted for mortality, will be the trial’s primary efficacy outcome.

The PHOENIX trial design builds upon the positive data obtained from the Phase II CENTAUR clinical trial.

Amylyx Co-CEOs Joshua Cohen and Justin Klee said: “We are grateful for the people living with ALS and their families who are participating in PHOENIX and the dedication of the study investigators.

“We remain committed to continuing research and exploring the full potential of AMX0035 as part of our mission to one day end the suffering caused by ALS and other neurodegenerative diseases.”

The company expects to receive topline results from the PHOENIX trial in 2024.