Vertex Pharmaceuticals rose nearly 7% to an all-time high on Monday after Sionna Therapeutics said SION-719 failed a mid-stage cystic fibrosis trial, removing what investors had viewed as one of the clearest threats to Trikafta. Sionna shares fell more than 90% to a record low after the add-on therapy missed the primary endpoint in the PreciSION CF Phase 2a proof-of-concept study, showing a -1.0 mmol/L mean placebo-adjusted change in sweat chloride with a p-value of 0.7 in combination with Trikafta. Sionna said it received the data on August 7, 2026, and is reviewing potential confounders including unexpected variability in individual sweat chloride levels and differences in Trikafta exposure between treatment periods. The company said SION-719 was generally well tolerated over 14 days, with mostly mild-to-moderate treatment-emergent adverse events and no serious adverse events or liver function trends, but it will not advance the candidate further. Separately, Sionna said a Phase 1 trial of SION-451 in proprietary dual combinations with SION-2222 or SION-109 met safety, tolerability and pharmacokinetic objectives in healthy subjects, and it selected SION-451 plus SION-2222 as its preferred regimen based on overall data and target coverage. The outcome leaves Trikafta as the standard of care and gives Vertex more time to build new businesses in pain, kidney disease and gene editing, while second-quarter revenue rose 12% to roughly $3.33 billion and full-year guidance increased to $13.1 billion to $13.2 billion.