Sionna Therapeutics, Inc. 4

OrbiMed Advisors LLC and OrbiMed Capital GP VIII LLC, on behalf of OrbiMed Private Investments VIII, LP, sold 85,918 shares of Sionna Therapeutics, Inc. common stock at $44.86 per share under a 10b5-1 plan.

On July 7, 2026, OrbiMed Advisors LLC and OrbiMed Capital GP VIII LLC, as reporting persons for OrbiMed Private Investments VIII, LP, sold 85,918 shares of Sionna Therapeutics, Inc. common stock at an average price of $44.86 per share under a Rule 10b5-1 trading plan, for total proceeds of approximately $3.86 million. Following this disposition, the reporting group continued to beneficially own 2,469,959 shares of Sionna Therapeutics indirectly through OPI VIII, with OrbiMed Advisors and OrbiMed Capital GP VIII disclaiming beneficial ownership beyond their pecuniary interests and noting that OrbiMed has designated Peter A. Thompson to serve on the issuer’s board of directors.

Filing Facts

CIK

2036042

Ticker

SION

Form

4

Source Type

fda

Accession

0000947871-26-000694

Alert Tier

7