Sionna Therapeutics Investigation Notice: Levi & Korsinsky Notifies Investors of Pending Investigation Into Sionna Therapeutics (SION)

Sionna Therapeutics told investors its SION-719 program was on track; the Phase 2a Trial Failed Key Endpoint and stock lost roughly 90% of its value.

NEW YORK, Aug. 12, 2026 /PRNewswire/ -- Sionna Therapeutics (NASDAQ: SION) shareholders watched roughly 90% of their investment disappear after the Company reported that its 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 advance as an add-on therapy. If you lost money on SION, 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.

The reported result: a placebo-adjusted sweat chloride change of -1.0 mmol/L, with a p-value of 0.7, when SION-719 was added to standard of care. Sionna stated it would not advance SION-719 as an add-on therapy. In its FY2025 Form 10-K, the Company had disclosed that it was "substantially dependent on the success of at least one of our nucleotide binding domain 1 ('NBD1') stabilizers."

The collapse was not attributed to a liquidity shortfall. Sionna reported approximately $268.3 million in cash, cash equivalents and marketable securities as of June 30, 2026, and a Q2 2026 net loss of $29.9 million. The investigation concerns whether Sionna's public statements regarding the SION-719 program adequately reflected the clinical and regulatory risk before the readout.

Investors who purchased SION shares and suffered losses may request a no-cost review of their potential recovery, or contact Joseph E. Levi, Esq. at (212) 363-7500.

WHY LEVI & KORSINSKY -- Ranked in ISS Securities Class Action Services' Top 50 Report for seven consecutive years, Levi & Korsinsky, LLP is a nationally recognized leader in shareholder rights litigation. With a team of over 70 professionals, the firm has recovered hundreds of millions of dollars for investors.

Frequently Asked Questions About the SION Investigation

Q: Which statements are being investigated as potentially misleading? A: The investigation concerns whether Sionna Therapeutics made materially false or misleading statements regarding the development status and prospects of its SION-719 program. When the Company disclosed that the Phase 2a PreciSION CF trial missed its key sweat chloride endpoint and that SION-719 would not advance as an add-on therapy, the stock price declined sharply.

Q: How much did SION stock drop? A: Shares fell approximately 90% after the Company disclosed the Phase 2a trial result of -1.0 mmol/L placebo-adjusted sweat chloride change and its decision not to advance SION-719 as an add-on therapy. Investors who purchased shares at allegedly inflated prices and suffered losses may be eligible to seek compensation.

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: 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 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.

Q: Do I need to go to court or give testimony? A: No. Participating in the investigation does not require court appearances or depositions. If legal action is later pursued, the overwhelming majority of affected investors never appear in court either.

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