Hundreds of Millions and the Very Existence of Amylyx Pharmaceuticals Could be in Question as Phase 3 ALS Study Flops

Late last week, Amylyx Pharmaceuticals, Inc. (NASDAQ: AMLX) announced topline results from PHOENIX, a global, 48-week, randomized, placebo-controlled Phase 3 clinical trial of AMX0035 (sodium phenylbutyrate and taurursodiol [also known as ursodoxicoltaurine]; RELYVRIO^® in the U.S., ALBRIOZA™ in Canada) in people living with amyotrophic lateral sclerosis (ALS). The company’s data did not meet the established study endpoints. By September 2022, the U.S. Food and Drug Administration (FDA) approved AMX0035 for the treatment of ALS. Back then, the company worked with the FDA Advisory Committee to give a thumbs up on the drug based only on Phase 2 data. The company committed, however, to voluntarily withdraw the drug should the data from their ongoing PHOENIX study not meet the study protocol’s primary endpoint of reaching statistical significance (p=0.667) as measured by change from baseline in the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) total score at Week 48. No statistical significance was seen in secondary endpoints.

So, the latest results mean that the company failed to meet the study’s primary endpoint as part of the ongoing multi-site international study involving 664 LS patients. The study failed to inhibit disease advancement when compared to the placebo. Moreover, secondary endpoints such as qualitative measure of quality of life and muscle function also flopped.