360° Insights: Amylyx's Relyvrio

Amylyx’s Relyvrio (sodium phenylbutyrate and taurursodiol; formerly AMX0035) is an oral, fixed-dose combination therapy approved by the FDA on September 29, 2022, for the treatment of amyotrophic lateral sclerosis (ALS). Relyvrio is designed to target the endoplasmic reticulum and mitochondrial-dependent neuronal degeneration pathways. Amylyx is also investigating AMX0035 for the potential treatment of Alzheimer's disease and Wolfram syndrome.

​ALS is a rare, fatal, progressive neurodegenerative disorder that affects upper and lower motor neurons. A loss of motor neurons in the brain and spinal cord initially leads to focal weakness, with muscle weakness spreading over time. Most patients die of respiratory failure within 2 to 5 years of symptom onset.
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Currently, there are no treatments that stop or significantly slow the progression of ALS. Prior to the approval of Relyvrio, riluzole and Mitsubishi Tanabe’s Radicava/Radicava ORS (edaravone) were the only two drugs approved by the FDA to treat the disease; however, each of these three treatments has only been shown to provide a modest benefit.

Amylyx has initiated the Phase 3, placebo-controlled PHOENIX trial to evaluate the efficacy and safety of Relyvrio. Given that Relyvrio received a traditional approval from the FDA, confirmatory results from this trial are not required for ongoing approval. The results, however, will be of interest, as questions have been raised regarding Relyvrio’s efficacy. Herein, we provide a selection of key points included in our full reports.