Company: SION
Filing Date: 2025-01-17
Form Type: S-1
Source: 0001193125-25-008474
Chunk: 242

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-01-17
Form: S-1
Chunk 242
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 business judgment based on all material information reasonably available to him or her. Consequently, an officer or director will not be personally liable to us or our stockholders for monetary damages or breach of fiduciary duty as an officer or director, except for liability for:

| • |     | any breach of the officer or director’s duty of loyalty to us or our stockholders; |

| • |     | any act or omission not in good faith or that involves intentional misconduct or a knowing violation of law; |

| • |     | for our directors, unlawful payments of dividends or unlawful stock repurchases, or redemptions as provided in Section 174 
 of the Delaware General Corporation Law (the “DGCL”);                                                                      |

| • |     | for our officers, any derivative action by or in the right of the corporation; or |

| • |     | any transaction from which the officer or director derived an improper personal benefit. |

These limitations of liability do not limit or eliminate our rights or any stockholder’s rights to seek non-monetary relief, such as injunctive relief or rescission. These provisions will not alter an officer or director’s liability under other laws, such as the federal securities laws or other state or federal laws. Our fifth amended and restated certificate of incorporation that will become effective immediately prior to the completion of this offering also authorizes us to indemnify our officers, directors and other agents to the fullest extent permitted under Delaware law. As permitted by Delaware law, our amended and restated bylaws, which will become effective upon the effectiveness of this registration statement will provide that:

| • |     | we will indemnify our directors, officers, employees and other agents to the fullest extent permitted by law; |

| • |     | we must advance expenses to our directors and officers, and may advance expenses to our employees and other agents, in 
 connection with a legal proceeding to the fullest extent permitted by law; and                                         |

| • |     | the rights provided in our amended and restated bylaws are not exclusive. |

If Delaware law is amended to authorize corporate action further eliminating or limiting the personal liability of a director or officer, then the liability of our directors or officers will be so eliminated or limited to the fullest extent permitted by Delaware law, as so amended. Our amended and restated 177

bylaws will also permit us to secure insurance on behalf of any officer, director, employee or other agent for any liability arising out of his or her actions in connection with their services to