Amylyx Surges 33% as Avexitide Hits Primary and All Secondary Endpoints in Phase 3 LUCIDITY Trial

Amylyx Pharmaceuticals, Inc. (NASDAQ: AMLX), a clinical-stage pharmaceutical company, announced positive topline results on August 18, 2026 from the Phase 3 LUCIDITY trial of avexitide in post-bariatric hypoglycemia (PBH). The trial met its FDA-agreed-upon primary endpoint, with avexitide reducing the composite rate of Level 2 and Level 3 hypoglycemic events by 55% versus placebo (p=0.000003), and hit every secondary endpoint across both self-monitored fingerstick testing and continuous glucose monitoring. Shares jumped 14% after the Monday announcement that results were coming, then surged another 33% to $28.38 in premarket trading Tuesday, marking Amylyx’s largest single-day percentage gain since September 2022.

A Receptor Antagonist That Works the Opposite Way From Zepbound and Wegovy

LUCIDITY enrolled 78 participants with PBH following Roux-en-Y gastric bypass surgery, a procedure that reduces the stomach to roughly the size of an egg. Patients with PBH represent about 8% of all bariatric surgery patients, translating to an estimated 160,000 to 167,000 people in the United States living with the condition. After surgery, food moves through the intestines far faster than normal, prompting the body to release the GLP-1 hormone at levels 10 to 20 times higher than typical post-meal amounts. That overproduction causes blood sugar to crash sharply regardless of what or how much a patient eats. Avexitide works by binding to GLP-1 receptors on pancreatic cells and blocking the hormone from over-signaling—the direct inverse mechanism of GLP-1 agonists like Zepbound and Wegovy, which stimulate insulin secretion to lower blood sugar in diabetes and obesity. Because avexitide suppresses rather than mimics the hormone, Amylyx reported no changes in body weight in either treatment arm, and the drug was generally well tolerated, with diarrhea and injection-site redness and bruising the most common side effects.

An Analyst Sees $1.5 Billion in Peak Sales as Amylyx Targets a Year-End NDA

Leerink analyst Marc Goodman projected avexitide could reach $1.5 billion in peak annual sales in a note published ahead of the readout, with an expected price point around $150,000. Amylyx holds FDA Breakthrough Therapy designation for avexitide and plans to submit a new drug application by the end of 2026, positioning the company for a potential 2027 launch. The company also develops a longer-acting GLP-1 receptor antagonist, AMX0318, targeting PBH and other rare diseases, and continues Phase 2 development of AMX0035 in Wolfram syndrome. Amylyx reported $250.8 million in cash and marketable securities as of June 30, 2026, down from $279.8 million at the end of Q1, with a cash runway reaffirmed into 2028—giving the company runway through the NDA filing and initial commercial launch preparations without an imminent capital raise.

The LUCIDITY Win Completes a Dramatic Turnaround From the Relyvrio Collapse

The scale of Tuesday’s stock move reflects how far Amylyx has come since its near-collapse. Relyvrio (AMX0035) received full FDA approval for ALS in 2022 after two advisory committee hearings, a rarity that patient advocates hailed as a watershed moment given how few effective ALS treatments exist. But the drug’s Phase 3 confirmatory trial failed cleanly in early 2024, with no silver linings in the data, and Amylyx withdrew Relyvrio from the market. The stock crashed roughly 85% at the time. Searching for a new direction, co-CEOs Justin Klee and Joshua Cohen acquired avexitide from Eiger BioPharmaceuticals for $35.1 million just months later, purchasing the already Phase 2-tested asset out of Eiger’s bankruptcy proceedings. Klee has downplayed the company’s ALS identity despite Relyvrio’s high profile, telling Endpoints News that Amylyx never set out to be an ALS company but followed where the science led. The company retains one ALS program, AMX0114, an antisense oligonucleotide targeting calpain-2 having fully enrolled its first two Phase 1 dosing cohorts and now enrolling its third, but avexitide now stands as Amylyx’s primary focus.

Strategic Investment Summary

• Phase 3 Success: Amylyx (NASDAQ: AMLX) announced on August 18, 2026 that avexitide met its primary endpoint in the Phase 3 LUCIDITY trial, reducing severe hypoglycemic events by 55% versus placebo (p=0.000003), and hit all secondary endpoints; shares surged 33% to $28.38 in premarket trading.
• Mechanism and Safety: Avexitide is a GLP-1 receptor antagonist, working opposite to agonists like Zepbound and Wegovy; the trial recorded no body weight changes in either arm and mostly mild to moderate side effects, primarily diarrhea and injection-site reactions.
• Market Opportunity: PBH affects an estimated 160,000 to 167,000 people in the U.S., about 8% of all bariatric surgery patients; Leerink analyst Marc Goodman projects $1.5 billion in peak annual sales at an estimated $150,000 price point.
• Regulatory Path: Avexitide holds FDA Breakthrough Therapy designation; Amylyx plans to submit an NDA by the end of 2026 and targets a 2027 commercial launch, with cash runway reaffirmed into 2028 on $250.8 million in cash and marketable securities as of June 30, 2026.
• Turnaround Context: Amylyx acquired avexitide for $35.1 million from Eiger BioPharmaceuticals’ bankruptcy proceedings in 2024, months after Relyvrio’s Phase 3 confirmatory failure and market withdrawal triggered an approximately 85% stock decline.
• Remaining Pipeline: Beyond avexitide, Amylyx advances AMX0318 (a longer-acting GLP-1 antagonist for PBH and other rare diseases), AMX0035 in Phase 2 for Wolfram syndrome, and AMX0114, an ALS-targeted antisense oligonucleotide in Phase 1 recruitment.

Find out more about the latest clinical updates and financial reports at the Amylyx Pharmaceuticals investor portal.