Avexitide

CAMBRIDGE, Mass.--(BUSINESS WIRE)-- Amylyx Pharmaceuticals, Inc. (Nasdaq: AMLX) (“Amylyx” or the “Company”) today announced the pricing of an underwritten public offering of 17,500,000 shares of its common stock at a public offering price of $10.00 per share. All of the shares of common stock are being offered by Amylyx. In addition, Amylyx has granted the underwriters a 30-day option to purchase up to an additional 2,625,000 shares of its common stock at the public offering price per share, less underwriting discounts and commissions. The gross proceeds to Amylyx from this offering are expected to be $175.0 million, before deducting underwriting discounts and commissions and offering expenses and excluding any exercise of the underwriters’ option to purchase additional shares. Amylyx intends to use the net proceeds from this offering, together with existing cash, cash equivalents and marketable securities, for: Avexitide commercial readiness; Research and development; and Working capital and other general corporate purposes. The offering is expected to close on or about September 11, 2025, subject to the satisfaction of customary closing conditions. Leerink Partners and Guggenheim Securities are acting as lead bookrunning managers for the offering. H.C. Wainwright & Co. is acting as lead manager for the offering. The shares described above are being offered pursuant to a shelf registration statement on Form S-3 (File No. 333-285525) that was filed with the Securities and Exchange Commission (the “SEC”) on March 4, 2025 and declared effective by the SEC on March 26, 2025. This offering is being made only by means of a prospectus supplement and an accompanying prospectus that form a part of the registration statement. A preliminary prospectus supplement and accompanying prospectus relating to the offering were filed with the SEC on September 9, 2025, and are available on the SEC’s website located at www.sec.gov. A final prospectus supplement containing additional information relating to the offering and accompanying prospectus will be filed with the SEC and will be available on the SEC’s website at www.sec.gov. When available, copies of the final prospectus supplement and the accompanying prospectus relating to this offering may also be obtained by contacting: Leerink Partners LLC, Syndicate Department, 53 State Street, 40th Floor, Boston, MA 02109, or by telephone at (800) 808-7525 ext. 6105, or by email at syndicate@leerink.com; and Guggenheim Securities, LLC, Attention: Equity Syndicate Department, 330 Madison Avenue, 8th Floor, New York, NY 10017, telephone: (212) 518-9544, email: GSEquityProspectusDelivery@guggenheimpartners.com. This press release shall not constitute an offer to sell or a solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of that state or jurisdiction. About Amylyx Pharmaceuticals Amylyx’ mission is to usher in a new era of treating diseases with high unmet needs. Where others see challenges, Amylyx sees opportunities and pursues them with urgency, rigorous science, and unwavering commitment to the communities it serves. Amylyx is currently focused on three investigational therapies across several endocrine and neurodegenerative diseases in which it believes it can make the greatest impact. Forward-Looking Statements Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including with respect to the completion of the offering, the potential exercise by the underwriters of the option to purchase additional shares, the anticipated closing date of the offering, the expected gross proceeds from the offering and the expected use of proceeds from the offering. No assurance can be given that the offering will be completed. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Any forward-looking statements in this press release are based on management’s current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. Risks that contribute to the uncertain nature of the forward-looking statements include those risks and uncertainties set forth in Amylyx’ SEC filings, including Amylyx’ Annual Report on Form 10-K for the year ended December 31, 2024, Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2025 and its subsequent filings with the SEC. All forward-looking statements contained in this press release speak only as of the date on which they were made. Amylyx undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Amylyx. Media Amylyx Media Team (857) 320-6191 amylyxmediateam@amylyx.com Investors Lindsey Allen (857) 320-6244 Investors@amylyx.com

Amylyx has discontinued the phase 2b trial and is tossing plans for the phase 3 portion of the study.\n Amylyx’s withdrawn-from-market Relyvrio has failed to make an impact on primary or secondary endpoints in a rare neurodegenerative disease, prompting the company to discontinue the program.Oral therapy Relyvrio, which Amylyx is again referring to as AMX0035, was tested in progressive supranuclear palsy (PSP), a fatal and rapidly progressing condition that impacts mobility, eye movements, swallowing and speech. Currently, there aren’t any approved treatments for the disease.Amylyx’s phase 2/3b study was measuring AMX0035’s impact on disease progression and severity using a 28-item, condition-specific scale. The phase 2 portion of the trial found no difference in patients receiving AMX0035 compared to placebo at 24 weeks, according to an Aug. 27 company release.Given the results, the company has discontinued the phase 2b trial, plus a related open-label extension study. Amylyx has also terminated plans for the phase 3 portion of the study.The company noted that AMX0035 was generally well-tolerated, with safety data consistent with prior studies.“We set a high bar for AMX0035 in PSP and made a commitment to base our decision-making on the totality of the data and the potential for clinically meaningful outcomes for those living with PSP,” Amylyx Chief Medical Officer Camille Bedrosian, M.D., said in the release. “While we are disappointed in these results, we believe these data will inform the PSP trial literature as well as deepen scientific understanding of this devastating disease.” AMX0035 is a combination of sodium phenylbutyrate and taurursodiol that was previously sold as Relyvrio and Albrioza for amyotrophic lateral sclerosis (ALS). The therapy had notched FDA approval in September 2022 based on phase 2 evidence that it significantly slowed the loss of physical function in patients with ALS.But a few months later, Amylyx said Relyvrio had failed a phase 3 trial, missing all primary and secondary endpoints measuring functional improvement in ALS. Shortly thereafter, Amylyx chose to pull the drug from the market. Amylyx still believes that the drug could offer benefits in Wolfram syndrome, a rare genetic disease that impacts about 3,000 Americans. The company is currently testing the therapy among 12 patients in an open-label phase 2 study.The company’s highest priority, however, is avexitide, a potentially first-in-class GLP-1 in development for post-bariatric hypoglycemia. The asset was purchased from Eiger Biopharma in 2024 and is currently being evaluated in a phase 3 trial, dubbed Lucidity. Patient recruitment for the study is expected to wrap by the end of this year, with topline data slated for 2026.The company currently expects its cash runway to last through the end of 2026.