Sionna Therapeutics SION-719 Trial Failure

Sionna Therapeutics reported that its Phase 2a PreciSION CF trial of SION-719 failed to achieve its key activity endpoint for sweat chloride reduction, with a placebo-adjusted change of -1.0 mmol/L (p=0.7) when added to standard of care. The company stated it would not advance SION-719 as an add-on therapy. Following the disclosure on August 10, 2026, Sionna's stock plunged approximately 90%, from the mid-$40s to roughly $4 per share, erasing about 92% of market value. The company reported $268.3 million in cash and equivalents as of June 30, 2026, and a Q2 2026 net loss of $29.9 million, with runway into 2028. Levi & Korsinsky, LLP launched an investigation into whether Sionna made materially misleading statements regarding the SION-719 program before the readout.