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. 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.

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.

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.

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.

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.

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.

Brokerage statements or trade confirmations showing purchase dates, share quantities, prices paid, and any subsequent sale dates and prices.

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.

There is no upfront cost to submit your information and review whether you may be eligible to recover.