The Law Offices of Howard G. Smith launched an investigation into Sionna Therapeutics on August 18, 2026. The firm is investigating potential violations of federal securities laws.
Sionna announced on August 10 that its clinical trial missed its primary endpoint. The trial tested SION-719 as a treatment for cystic fibrosis. This study was a Phase 2a clinical trial. Sionna will not advance the drug as an add-on to standard of care.
Sionna's stock price plummeted 91.2% following the announcement. The shares closed at a price of $4.10. This closing price was recorded on August 10.
The investigation examines whether the company made misleading statements. It also evaluates if Sionna failed to disclose material risks to investors.