Cystic fibrosis challenger Sionna Therapeutics disclosed that its Phase 2 add-on strategy failed to improve sweat chloride versus Vertex’s Trikafta alone, sending shares down sharply and removing a potential route to build incremental CFTR-modulating regimens. The company said it would preserve capital while evaluating next steps after SION-719 plus Trikafta missed the statistical bar on the primary biomarker. In parallel, Tenax Therapeutics reported negative results from its Phase 3 LEVEL trial of oral levosimendan (TNX-103) in pulmonary hypertension due to heart failure with preserved ejection fraction, where the six-minute walk distance difference did not reach statistical significance. The primary endpoint missed despite prespecified subgroup signals and “very encouraging” biomarker comments that analysts said were difficult to fully reconcile with the overall readout. Together, the setbacks show how biomarker-driven trials still face execution and placebo-response challenges, and how quickly capital markets react when incremental efficacy thresholds are not met in high-expectation therapeutic categories.