Sionna Therapeutics, Inc. (NASDAQ: SION)

This investigation is for anyone who acquired securities in Sionna Therapeutics, Inc. (NASDAQ: SION) prior to August 10, 2026.

The Law Offices of Howard G. Smith believes that the Company and certain of its executives violated federal law. Specifically, the Law Offices of Howard G. Smith believes that, in the Prospectus to the Company’s IPO, the Company misled investors regarding its financial condition. More specifically, the Law Offices of Howard G. Smith believes that the Company misled investors by telling investors that the Company developed a model where the Company could tell in advance whether drug candidates would succeed in clinical trials, and that the Company’s SION-719 would succeed in trials as an add-on to Trikafta as the standard of care for the treatment of patients with cystic fibrosis, when the Company knew or should have known that its model was not predictive.

On August 10, 2026, Sionna reported topline data from its PreciSION CF Phase 2a trial and provided a corporate update. Among other items, Sionna announced a primary endpoint miss and that the Company will not advance SION-719 as an add-on to standard of care. On this news, the price of the Company’s stock dropped precipitously on unusually heavy trading volume and continues to trade below the IPO price at this time.

The Law Offices of Howard G. Smith seeks to recover damages on behalf of class members. If you acquired securities in Sionna Therapeutics, Inc. (NASDAQ: SION) prior to August 10, 2026 you may join the lawsuit by submitting your information online, or you may call the Law Offices of Howard G. Smith and speak to Mr. Smith directly to learn how he can protect your rights.