Sionna Therapeutics (SION) Securities Investigation Notice - Levi & Korsinsky

Sionna Therapeutics Shares Lost Roughly 90% of Their Value After Phase 2a PreciSION CF Trial of SION-719 Failed to Achieve Its Key Sweat Chloride Endpoint.

NEW YORK, Aug. 19, 2026 /PRNewswire/ -- Sionna Therapeutics (NASDAQ: SION) shares collapsed approximately 92% after the Company disclosed that its Phase 2a PreciSION CF trial of SION-719 failed to achieve its key activity endpoint and that it would not advance the candidate as an add-on therapy. If you suffered a loss on your Sionna Therapeutics investment, you are encouraged to click here to submit your information . You may also contact Joseph E. Levi, Esq. via email at [email protected]  or by telephone at (212) 363-7500.

According to the Company's disclosure, SION-719 -- administered on top of standard of care -- produced a placebo-adjusted sweat chloride change of -1.0 mmol/L, with a p-value of 0.7. Sionna stated it would not advance SION-719 as an add-on therapy. The decline did not follow an apparent liquidity shortfall: Sionna reported approximately $268.3 million in cash, cash equivalents and marketable securities as of June 30, 2026, and a second-quarter net loss of $29.9 million.

Sionna's NBD1 stabilizer programs are central to its cystic fibrosis pipeline. The Company's FY2025 Form 10-K stated that it was "substantially dependent on the success of at least one of our nucleotide binding domain 1 ('NBD1') stabilizers." The investigation concerns whether SION investors received adequate disclosure regarding the Company's reliance on its NBD1 stabilizer programs and the risks associated with the SION-719 program.

Shareholders who lost money on SION are encouraged to request a no-cost review of your losses  or call (212) 363-7500.

ABOUT LEVI & KORSINSKY, LLP  -- Over the past 20 years, Levi & Korsinsky has secured hundreds of millions of dollars for aggrieved shareholders. The firm has extensive expertise in complex securities litigation and a team of over 70 employees. For seven consecutive years, Levi & Korsinsky has ranked in ISS Securities Class Action Services' Top 50 Report.

Frequently Asked Questions About the SION Investigation

Q: Who is conducting the SION investigation?  A: Levi & Korsinsky, LLP is investigating potential securities fraud claims on behalf of investors who purchased SION securities. The firm is nationally recognized, ranked in the ISS Top 50 for seven consecutive years, and has recovered hundreds of millions of dollars for aggrieved investors.

Q: Who is eligible to participate in the SION investigation?  A: Investors who purchased SION stock or securities and suffered financial losses may be eligible. Eligibility is based on purchase date and documented losses -- not on whether you still hold the shares.

Q: How much did SION stock drop?  A: Shares fell approximately 92% after the Company disclosed that the Phase 2a PreciSION CF trial of SION-719 failed to achieve its key activity endpoint for sweat chloride reduction and that the candidate would not be advanced as an add-on therapy. Investors who purchased shares and suffered losses may be eligible to seek recovery.

Q: What do SION investors need to do right now?  A: Investors may gather brokerage records showing purchase dates, share quantities, and prices paid. Submit your information for a no-cost, no-obligation evaluation of your potential recovery . No immediate action is required to remain eligible to participate in the investigation.

Q: What documents do I need to participate?  A: Brokerage statements or trade confirmations showing purchase dates, share quantities, prices paid, and any subsequent sale dates and prices.

Q: What if I already sold my SION shares -- can I still recover losses?  A: Yes. Eligibility is based on when you purchased, not whether you still hold the shares. Investors who bought SION and sold at a loss may still participate in the investigation.

Q: What if my SION losses are small -- is it still worth contacting a lawyer?  A: Yes. There is no minimum loss amount required to participate in the investigation.

Q: What does it cost me to participate?  A: There is no upfront cost to submit your information and review whether you may be eligible to recover. Should you choose to participate in any resulting action, these matters are generally handled on a contingency basis, with any attorneys' fees and expenses subject to court approval.

CONTACT:\
Levi & Korsinsky, LLP\
Joseph E. Levi, Esq.\
Ed Korsinsky, Esq.\
33 Whitehall Street, 27th Floor\
New York, NY 10004\
[email protected]\
Tel: (212) 363-7500\
Fax: (212) 363-7171

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SOURCE Levi & Korsinsky, LLP