Amylyx Pharmaceuticals SEC Filings

Amylyx Pharmaceuticals filed a Current Report (Form 8-K) that includes an underwriting agreement dated September 9, 2025, and counsel materials from Goodwin Procter LLP. The filing discloses that an opinion and consent of Goodwin Procter LLP are included as exhibits, and that the cover page interactive data file is embedded within the Inline XBRL document. The report contains a standard forward-looking statements caution referencing prior SEC reports and urges investors not to rely solely on forward-looking statements. The filing is signed by James M. Frates, Chief Financial Officer, dated September 10, 2025.

Amylyx Pharmaceuticals (AMLX) is offering shares under a shelf registration with a base offering of 17,500,000 shares at $10.00 per share, representing gross proceeds of $175,000,000 ($201,250,000 if the underwriters' option is exercised). Net proceeds are intended to advance avexitide commercial readiness and for R&D, working capital and general corporate purposes. Avexitide is a GLP-1 receptor antagonist being developed for post-bariatric hypoglycemia (PBH) and congenital hyperinsulinism; FDA granted Breakthrough Therapy, Rare Pediatric Disease and Orphan Drug designations for relevant indications. In April 2025 Amylyx dosed the first participant in the Phase 3 LUCIDITY trial in PBH (≈75 participants randomized 3:2 to 90 mg once daily or placebo); topline data are anticipated in H1 2026 with potential commercial launch in 2027 if approved. The prospectus also discloses clinical programs for AMX0035 (Wolfram syndrome Phase 2 open-label data through Week 48) and AMX0114 (Phase 1 LUMINA dosing began in Canada April 2025; ≈48 participants randomized 3:1).

Amylyx is advancing multiple clinical-stage programs with clear near-term catalysts. In April 2025 the company dosed the first participant in LUCIDITY, a pivotal Phase 3, randomized, double-blind, placebo-controlled 16-week trial of avexitide in post-RYGB post-bariatric hypoglycemia (PBH). Approximately 75 participants will be randomized 3:2 to 90 mg once daily or placebo; completers may enter a 32-week open-label extension. Recruitment is expected to finish in 2025 with topline data in H1 2026 and a potential commercial launch in 2027 if approved. Avexitide holds FDA Breakthrough Therapy, Rare Pediatric Disease and Orphan Drug designations for hyperinsulinemic hypoglycemia indications. Separately, AMX0035 showed sustained pancreatic function improvements through Week 48 in a Phase 2 Wolfram syndrome study and will inform Phase 3 planning. AMX0114 initiated first dosing in April 2025 in the Phase 1 LUMINA ALS trial (≈48 participants randomized 3:1; intrathecal dosing every 4 weeks up to four doses) with early cohort data expected in 2025. The prospectus notes proceeds will fund avexitide commercial readiness, R&D and general corporate purposes.

Amylyx Pharmaceuticals reported a key setback in its neurology pipeline. The company is discontinuing the ORION program of AMX0035 (sodium phenylbutyrate and taurursodiol) in adults living with progressive supranuclear palsy after the treatment did not show differences compared to placebo on primary or secondary outcomes at Week 24.

As a result, Amylyx will stop the ongoing Phase 2b trial and its open-label extension and will not start the planned Phase 3 portion of the program. The company noted that safety data in this study were consistent with safety data from prior AMX0035 studies, indicating no new safety concerns despite the lack of efficacy in this indication.

Gina Mazzariello, Chief Legal Officer of Amylyx Pharmaceuticals (AMLX), reported two Rule 10b5-1 sales totaling 30,000 common shares on August 12, 2025 and August 13, 2025. The August 12 sales comprised 15,000 shares at a weighted average price of $8.0735 (trades ranged $7.82–$8.27) and the August 13 sales comprised 15,000 shares at a weighted average price of $8.3364 (trades ranged $8.13–$8.47). After these transactions the reporting person beneficially owned 156,969 shares. The sales were executed under a 10b5-1 trading plan adopted on May 13, 2025. The Form 4 was filed and signed by an attorney in fact on August 14, 2025.

Amylyx Pharmaceuticals (AMLX) filed a Form 144 reporting a proposed sale of 30,000 common shares through Morgan Stanley Smith Barney LLC Executive Financial Services. The filing lists an aggregate market value of $234,600, an approximate sale date of 08/12/2025, and that the shares trade on NASDAQ. The filing reports 89,167,432 shares outstanding, meaning the 30,000-share notice represents approximately 0.034% of outstanding shares.

The securities were acquired as Restricted Stock Units from the issuer on 09/30/2024 and paid on that date. The filing reports "Nothing to Report" for securities sold in the past three months. Some standard Form 144 attestation language about material nonpublic information and Rule 10b5-1 is present, while several filer and issuer identification fields in the form appear blank or not provided.

Adage Capital Management, L.P., together with Robert Atchinson and Phillip Gross, reports shared beneficial ownership of 8,800,000 shares of Amylyx Pharmaceuticals, Inc. ("AMLX"). Those shares represent 9.87% of the company's common stock, based on an aggregate of 89,141,087 shares outstanding as of April 28, 2025. The holding is reported as shared voting and shared dispositive power of 8,800,000 shares, with 0 shares of sole voting or sole dispositive power.

The filing is submitted on Schedule 13G/A and includes a certification that the securities were acquired and are held in the ordinary course of business and not to influence control of the issuer.