Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 273

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 273
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 served as a non-employeemember of our board of directors during the fiscal year ended December 31, 2024 for their service on our board of directors during the year ended December 31, 2024. Non-employeedirectors Bruce Booth, Lucian Iancovici, H. Edward Fleming, Jr., Joshua Resnick, and Peter A. Thompson did not receive cash or equity compensation from us for their services as directors during 2024 due to their affiliation with Atlas Venture, TPG Growth, Enavate Sciences, RA Capital Management, L.P. and OrbiMed Advisors LLC, respectively. Our former non-employeedirector, Adam Rosenberg, also did not receive cash or equity compensation from us for his services as a director due to his former affiliation with RA Capital Management, L.P. and his former position as our chief executive officer prior to 2023. Other than as set forth in the table and described more fully below, we did not pay any compensation, make any equity awards or non-equityawards to, or pay any other compensation to any of the non-employeemembers of our board of directors in 2024. During the fiscal year ended December 31, 2024, Mr. Cloonan, our Chief Executive Officer, served as a member of our board of directors and received no additional compensation for his services as a member of our board of directors. The compensation for the fiscal year ended December 31, 2024 received by Mr. Cloonan, as an NEO, is presented in “ Executive Compensation—2024 Summary Compensation Table” above. 2024 Director Compensation Table

|                                  |     | Fees Earned or 
 Paid in Cash   
 ($)(1)         |        |     | Option Awards 
 ($)(2)        |         |     | Total ($) |         |
| Name                             |     |                |        |     |               |         |     |           |         |
| Paul Clancy, M.B.A.(3)           |     |                | 50,000 |     |               | 294,287 |     |           | 344,287 |
| Adam Rosenberg(4)                |     |                |      — |     |               |       — |     |           |       — |
| Bruce Booth, D.Phil.(5)          |     |                |      — |     |               |       — |     |           |       — |
| Lucian Iancov