Amylyx Shares Plummet On Skeptical FDA Adcomm Docs On ALS Drug

The FDA released its briefing documents for the advisory committee to discuss Amylyx Pharmaceuticals Inc's AMLX sodium phenylbutyrate/taurursodiol (AMX0035) powder for amyotrophic lateral sclerosis (ALS).
Agency statisticians called into question the Company's efficacy and survival analyses, raising concern that the modest survival benefit seen may potentially be due to underlying disease heterogeneity rather than an effect of the drug.
Among the issues cited by the FDA included questions about the functional rating scale used to measure disease progression. Regulators noted that the scale does not correlate well with early-stage and late-stage ALS.
The FDA Adcomm will meet on March 30 To Review Amylyx's ALS Drug.
In its application, Amylyx assumed this scale to be linear throughout the entire disease and came up with a p-value showing statistical significance (p=0.034).
But the FDA said a model with "a quadratic term" would more accurately capture the scale's measurements. A ba3ckup analysis using this model showed the drug did not significantly impact ALS progression (p-value of p=0.1134).
Regulators also took issue with Amylyx's inclusion of tracheostomies and hospitalizations as a measure of survival, given the "considerable variation" in when patients receive such treatments. The FDA says it regularly encourages companies not to do this.
Price Action: AMLX shares are down 31.40% at $17.15 during the market session on the last check Monday.