--- title: "Securities Fraud Investigation Into Sionna Therapeutics, Inc. (SION) Announced – Shareholders Who Lost Money Urged to Contact The Law Offices of Frank R. Cruz" type: "News" locale: "en" url: "https://longbridge.com/en/news/296150826.md" description: "The Law Offices of Frank R. Cruz announced a securities fraud investigation into Sionna Therapeutics, Inc. (NASDAQ: SION). The probe concerns potential violations of federal securities laws following the company's August 10, 2026 announcement of a primary endpoint miss in its PreciSION CF Phase 2a trial. This news caused SION's stock to plummet 91.2% to $4.10. Investors who lost money are urged to contact the law firm to inquire about pursuing claims for recovery." datetime: "2026-08-17T22:12:17.000Z" locales: - [zh-CN](https://longbridge.com/zh-CN/news/296150826.md) - [en](https://longbridge.com/en/news/296150826.md) - [zh-HK](https://longbridge.com/zh-HK/news/296150826.md) generator: "portal-rs" --- # Securities Fraud Investigation Into Sionna Therapeutics, Inc. (SION) Announced – Shareholders Who Lost Money Urged to Contact The Law Offices of Frank R. Cruz **Securities Fraud Investigation Into Sionna Therapeutics, Inc. (SION) Announced – Shareholders Who Lost Money Urged to Contact The Law Offices of Frank R. Cruz** The Law Offices of Frank R. Cruz announces an investigation of Sionna Therapeutics, Inc. (“Sionna” or the “Company”) (NASDAQ: SION) on behalf of investors concerning the Company’s possible violations of federal securities laws. **IF YOU ARE AN INVESTOR WHO LOST MONEY ON SIONNA THERAPEUTICS, INC. (SION), CLICK HERE TO INQUIRE ABOUT POTENTIALLY PURSUING A CLAIM TO RECOVER YOUR LOSS.** **What Is the Investigation About?** 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, Sionna's stock fell $46.54, or 91.2% per share, to close at $4.10 per share on August 10, 2026, thereby injuring investors. **Contact Us to Participate or Learn More:** If you purchased Sionna Therapeutics, Inc. securities, have information or would like to learn more about these claims, or have any questions concerning this announcement or your rights or interests with respect to these matters, please contact us: The Law Offices of Frank R. Cruz 2121 Avenue of the Stars, Suite 800 Century City, California 90067 Call us at: 310-914-5007 Email us at: info@frankcruzlaw.com Visit our website at: www.frankcruzlaw.com. Follow us for updates on Twitter at twitter.com/FRC\_LAW. If you inquire by email, please include your mailing address, telephone number, and number of shares purchased. This press release may be considered Attorney Advertising in some jurisdictions under the applicable law and ethical rules. The Law Offices of Frank R. Cruz, Los Angeles Frank R. Cruz 310-914-5007 fcruz@frankcruzlaw.com www.frankcruzlaw.com View source version on businesswire.com: https://www.businesswire.com/news/home/20260817255088/en/ ### Related Stocks - [SION.US](https://longbridge.com/en/quote/SION.US.md) ## Related News & Research - [22:22 ETRobbins LLP Reminds Stockholders it is Investigating the Recent Stock Drop of Sionna Therapeutics](https://longbridge.com/en/news/296425061.md) - [Robbins LLP is Investigating the Recent Stock Drop of Sionna Therapeutics; Contact the Firm for Information](https://longbridge.com/en/news/296143993.md) - [SION Investors Have Opportunity to Join Sionna Therapeutics, Inc. Fraud Investigation with SBS Law](https://longbridge.com/en/news/296031680.md) - [Starfighters Space, Inc. GAAP EPS of -$0.24](https://longbridge.com/en/news/296400745.md) - [08:36 ETBCA IT, Inc. Named No. 1700 on the 2026 Inc. 5000 List, the Most Prestigious Ranking of America's Fastest-Growing Private Companies](https://longbridge.com/en/news/296229672.md) --- > **Disclaimer: This article is for reference only and does not constitute any investment advice.**