SAN DIEGO, Aug. 12, 2026 /PRNewswire/ -- Robbins Geller Rudman & Dowd LLP is investigating potential violations of U.S. federal securities laws involving Sionna Therapeutics, Inc. (NASDAQ: SION). 

If you have information that could assist in the Sionna Therapeutics investigation or if you are a Sionna Therapeutics investor who suffered a loss and would like to learn more, you can provide your information here:

https://www.rgrdlaw.com/cases-sionna-therapeutics-inc-investigation-sion.html

You can also contact attorneys Ken Dolitsky or Michael Albert of Robbins Geller by calling 800/851-7783 or via e-mail at info@rgrdlaw.com.

THE COMPANY: Sionna Therapeutics is a clinical-stage biopharmaceutical company that researches and develops medicines for the treatment of cystic fibrosis.

THE REVELATION: On August 10, 2026, Sionna Therapeutics announced that its "SION-719 Phase 2a proof-of-concept trial did not achieve key activity endpoint of sweat chloride reduction when added to standard of care."  On this news, the price of Sionna Therapeutics stock fell more than 91%.

ABOUT ROBBINS GELLER: Robbins Geller Rudman & Dowd LLP is one of the world's leading law firms representing investors in securities fraud and shareholder rights litigation.  Our Firm ranked #1 on the most recent ISS Securities Class Action Services Top 50 Report, recovering more than $916 million for investors in 2025.  This marks our fourth #1 ranking in the past five years.  And in those five years alone, Robbins Geller recovered $8.4 billion for investors – $3.4 billion more than any other law firm.  With 200 lawyers in 10 offices, Robbins Geller is one of the largest plaintiffs' firms in the world, and the Firm's attorneys have obtained many of the largest securities class action recoveries in history, including the largest ever – $7.2 billion – in In re Enron Corp. Sec. Litig.

Past results do not guarantee future outcomes.
Services may be performed by attorneys in any of our offices. 

Contact:

Robbins Geller Rudman & Dowd LLP
Ken Dolitsky
Michael Albert
655 W. Broadway, Suite 1900, San Diego, CA 92101
800/851-7783
info@rgrdlaw.com 

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SOURCE Robbins Geller Rudman & Dowd LLP