Transaction Details

Footnotes

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any. | This option vests in full upon the earlier of June 12, 2026 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.