RA Capital Nexus Fund III, L.P. Sells 17,118 Shares of Sionna Therapeutics, Inc.

RA Capital Nexus Fund III, L.P., a 10% stockholder and director of Sionna Therapeutics, Inc., has filed a Form 144 with the SEC indicating the sale of 17,118 shares of common stock. The shares were acquired during the company's IPO on February 7, 2025, and were sold on October 28, 2025, for an aggregate market value of $675,305.10. The sale was executed through BTIG, LLC. This filing is a routine disclosure of stock sales by significant shareholders and does not indicate any fundamental changes in the company's operations or financial health.