Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 242

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 242
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 management the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and 
 Results of Operations” disclosures in our periodic reports filed with the SEC;                                                                                                                                           |

| • |     | oversee our risk management policies, procedures and practices, including those related to cybersecurity; and |

| • |     | approving, or, as permitted, pre-approving, audit and permissible non-audit services to be performed by the independent registered public accounting firm. |

Our audit committee will operate under a written charter, which will be effective upon the completion of this offering, that satisfies the applicable Nasdaq Listing Rules. Compensation Committee Our compensation committee currently consists of Joanne Louise Viney, Ph.D., the chair of our compensation committee, Lucian Iancovici, M.D., Bruce Booth, D.Phil. and Laurie Stelzer, M.B.A. Our board of directors has determined that each member of the compensation committee is independent under the Nasdaq Listing Rules and is a “non-employeedirector” as defined in Rule 16b-3promulgated under the Exchange Act. The primary purpose of our compensation committee is to discharge the responsibilities of our board of directors in overseeing our compensation policies, plans and programs and to review and determine the compensation to be paid to our executive officers, directors and other senior management, as appropriate. Specific responsibilities of our compensation committee include:

| • |     | annually reviewing and recommending to our board of directors the corporate goals and objectives relevant to the 
 compensation of our Chief Executive Officer;                                                                     |

| • |     | evaluating the performance of our Chief Executive Officer in light of such corporate goals and objectives and, based on 
 such evaluation, recommending to our board of directors the cash compensation of our Chief Executive Officer;           |

| • |     | reviewing and approving the compensation arrangements with our other executive officers and certain other senior 
 management;                                                                                                      |

| • |     | reviewing and recommending to our board of directors the compensation paid to our directors; |

| • |     | administering our equity incentive plans and other benefit programs; |

| • |     | overseeing and administering our compensation and similar plans; and |

| • |     | reviewing and establishing general policies relating to compensation and benefits of our employees, including our overall 
 compensation philosophy.                                                                                                  |

Our compensation committee will operate under a written charter, which will be effective upon the completion of this offering, that satisfies the applicable Nasdaq Listing Rules. 176

Nominating and Corporate Governance Committee Our nominating and corporate