Company: SION
Filing Date: 2025-04-29
Form Type: DEF 14A
Source: 0001193125-25-101830
Chunk: 22

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-04-29
Form: DEF 14A
Chunk 22
---
 a position on our board of directors are as follows:

| • |     | Nominees should demonstrate high standards of personal and professional ethics and integrity. |

| • |     | Nominees should have proven achievement and competence in the nominee’s field and the ability to exercise sound business judgment. |

| • |     | Nominees should have skills that are complementary to those of the existing board of directors. |

| • |     | Nominees should have the ability to assist and support management and make significant contributions to the company’s success. |

| • |     | Nominees should have an understanding of the fiduciary responsibilities that are required of a member of the board of directors and the commitment of time and energy necessary to diligently carry out those responsibilities. |

**Once candidates have been identified, the nominating and corporate governance committee will confirm that the candidates meet all of the minimum qualifications for director nominees established by the nominating and corporate governance committee. The nominating and corporate governance committee may gather information about the candidates through interviews, detailed questionnaires, comprehensive background checks or any other means that the nominating and corporate governance committee deems to be appropriate in the evaluation process. The nominating and corporate governance committee will then meet as a group to discuss and evaluate the qualities and skills of each candidate, both on an individual basis and taking into account the overall composition and needs of our board of directors. Based on the results of the evaluation process, the nominating and corporate governance committee will recommend candidates for the board of directors’ approval to fill a vacancy or as director nominees for election to the board of directors by our stockholders each year in the class of directors whose term expires at the relevant annual meeting. Stockholders may recommend individuals to the nominating and corporate governance committee for consideration as potential director candidates. Any such proposals should be submitted to our corporate secretary at our principal executive offices no later than the close of business on the 90 thday nor earlier than the close of business on the 120 thday prior to the one-yearanniversary of the date of the preceding year’s annual meeting and should include appropriate biographical and background material to allow the nominating and corporate governance committee to properly evaluate the potential director candidate and the number of shares of our stock 15

beneficially owned by the stockholder proposing the candidate. Stockholder proposals should be addressed to Sionna Therapeutics, Inc., 21 Hickory Drive, Suite 500, Waltham, MA 02451, Attention: Chief Legal Officer