Amylyx Pharmaceuticals stock shot up more than 42% at one stage ahead of Tuesday's opening bell after the company said its investigational GLP-1 receptor antagonist, avexitide, met both the primary and secondary endpoints in a late-stage clinical trial.

Researchers were probing the drug's efficacy in patients with post-bariatric hypoglycemia, a condition marked by low blood sugar after eating that typically emerges years after weight-loss surgeries. The Phase 3 trial met its primary endpoint, which had been agreed upon with regulators ahead of time, as patients taking the drug experienced 55% fewer severe hypoglycemic events than those taking a placebo. Additionally, the drug hit every secondary benchmark across all evaluation methods, including self-monitored fingerstick testing and continuous glucose monitoring.

Avexitide works by binding to GLP-1 receptors on cells in the pancreas, preventing the natural glucagon-like peptide-1 hormone from binding and over-signaling after meals. This mechanism is the direct inverse of popular GLP-1 medications like Zepbound and Wegovy, which instead mimic the hormone to stimulate insulin secretion and lower blood sugar.