SION ▼ -0.4% - Sionna Therapeutics, Inc. $SION - Sionna Therapeutics Announces Plans to Advance SION-451 + SION-2222 Dual Combination into Phase 2a Proof-of-Concept Trial Sionna Therapeutics shares declined 0.4% today despite the company's announcement that it plans to advance its dual combination therapy SION-451 + SION-2222 into a Phase 2a proof-of-concept trial. The modest decline suggests investors may have been expecting more aggressive clinical progress or additional catalysts to move the stock materially higher. 14-SEP-2026 04:01 PM ET