Amylyx Pharmaceuticals withdraws FDA approval for Relyvrio treatment.

Amylyx Pharmaceuticals has announced that the FDA has granted a voluntary request to withdraw approval of Relyvrio. The company is a commercial-stage biopharmaceutical firm focused on developing treatments for neurodegenerative diseases, including AMX0035 for Wolfram syndrome and progressive supranuclear palsy, and AMX0114 for amyotrophic lateral sclerosis.

Amylyx Pharmaceuticals, a commercial-stage biopharmaceutical firm focused on developing treatments for neurodegenerative diseases, has announced that the FDA has granted a voluntary request to withdraw approval of Relyvrio (AMX0035). The company is discontinuing its Relyvrio program for progressive supranuclear palsy (PSP) following the failure of the drug to meet primary and secondary endpoints in a phase 2/3b clinical trial [1].

Relyvrio, an oral therapy combination of sodium phenylbutyrate and taurursodiol, was tested in PSP, a fatal and rapidly progressing condition that impacts mobility, eye movements, swallowing, and speech. Currently, there are no approved treatments for PSP. The phase 2 portion of the trial found no difference in patients receiving Relyvrio compared to placebo at 24 weeks [1].

Given these results, Amylyx has discontinued the phase 2b trial and an open-label extension study, as well as plans for the phase 3 portion of the study. The company noted that Relyvrio was generally well-tolerated, with safety data consistent with prior studies [1].

Amylyx's Chief Medical Officer, Camille Bedrosian, M.D., stated, "While we are disappointed in these results, we believe these data will inform the PSP trial literature as well as deepen scientific understanding of this devastating disease" [1].

Amylyx remains committed to advancing potential new treatments for communities with high unmet needs. The company's highest priority is avexitide, a potentially first-in-class GLP-1 in development for post-bariatric hypoglycemia. Avexitide is currently being evaluated in a phase 3 trial, dubbed Lucidity [1].

The company's stock, AMLX, fell 4.2% to $9.1 premarket following the FDA's withdrawal of approval for Relyvrio [2]. The stock had more than doubled year-to-date before the announcement.

Amylyx continues to expect its cash runway to extend through the end of 2026 [1].

References:
[1] https://www.fiercebiotech.com/biotech/amylyx-axes-rare-disease-program-after-relyvrio-fails-beat-placebo
[2] https://www.tradingview.com/news/reuters.com,2025:newsml_L6N3UK0KL:0-amylyx-pharmaceuticals-falls-after-us-fda-withdraws-approval-for-als-drug/