Fixed-Dose Combo Therapy for ALS Gets Priority Review

Neuron system disease
AMX0035 is an oral, fixed-dose coformulation of sodium phenylbutyrate and taurursodiol, also known as ursodoxicoltaurine.

The Food and Drug Administration (FDA) has accepted for Priority Review the New Drug Application (NDA) for AMX0035 (sodium phenylbutyrate and taurursodiol) for the treatment of amyotrophic lateral sclerosis (ALS).

AMX0035 is an oral, fixed-dose coformulation of sodium phenylbutyrate and taurursodiol, also known as ursodoxicoltaurine. The application is supported by data from the randomized, double-blind, placebo-controlled phase 2 CENTAUR trial ( Identifier: NCT03127514), along with the open-label extension study ( Identifier: NCT03488524).

Results from CENTAUR showed that ALS patients receiving AMX0035 demonstrated statistically significant reduction in clinical decline at the end of the 6-month randomized phase, as measured by the Revised ALS Functional Rating Scale. After a follow-up of 3 years, a survival analysis showed that patients who received AMX0035 during the placebo-controlled phase of CENTAUR had a 44% lower risk of death compared with those who received placebo (hazard ratio, 0.56; 95% CI, 0.34-0.92). The median survival duration in the follow-up period was 25 months (95% CI, 19.0-33.6) in the AMX0035 arm and 18.5 months (95% CI, 13.5-23.2) in the placebo arm.

The treatment is also being evaluated in the double-blind, placebo-controlled phase 3 PHOENIX clinical trial ( Identifier: NCT05021536). An Expanded Access Program is also in the works for patients who are ineligible for participation in the PHOENIX study.

“There is a lot of progress in ALS research; and now with AMX0035’s NDA acceptance, we believe we are one step closer to a potential new treatment option,” said Merit Cudkowicz, MD, coprincipal investigator of the CENTAUR trial and cofounder of the Northeast ALS Consortium, Director of the Healey & AMG Center for ALS and Chair of Neurology at Massachusetts General Hospital and the Julieanne Dorn Professor of Neurology at Harvard Medical School. “We look forward to seeing AMX0035 potentially progress through the regulatory review process as we continue to investigate its therapeutic potential in the global phase 3 PHOENIX clinical trial as part of the collaboration with the Northeast ALS (NEALS) Consortium and the Treatment Research Initiative to Cure ALS (TRICALS) in Europe.”

A Prescription Drug User Fee Act target date of June 29, 2022 has been set for the NDA. An FDA advisory committee meeting is being planned to discuss the application.


Amylyx Pharmaceuticals announces FDA acceptance and Priority Review of New Drug Application (NDA) for AMX0035 for the treatment of ALS. News release. December 29, 2021.