Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 26

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 26
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 maintaining relationships with our third-party manufacturers and their ability to comply with current good manufacturing                                                                      
 practices (“cGMPs”), as well as making arrangements with our third-party manufacturers for commercial manufacturing capabilities at a cost and scale sufficient to support commercialization; |

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| • |     | establishing sales, marketing and distribution capabilities and launching commercial sales of our product candidates, if 
 and when approved, whether alone or in collaboration with others;                                                        |

| • |     | obtaining, establishing, maintaining and enforcing patent and any potential trade secret protection or regulatory 
 exclusivity for our product candidates;                                                                           |

| • |     | maintaining an acceptable safety profile of our product candidates following regulatory approvals, if any; |

| • |     | the sufficiency of our financial resources to fund our operations; and |

| • |     | maintaining and growing an organization of people who can develop and, if approved, commercialize, market and sell our 
 current or future product candidates.                                                                                  |

If we are unable to develop, receive marketing approval for and successfully commercialize our product candidates, or if we experience delays as a result of any of the above factors or otherwise, our business would be significantly harmed. We are early in our development efforts. If we are unable to successfully develop, receive regulatory approval for and commercialize any product candidate or successfully develop any other product candidate or experience significant delays in doing so, our business will be substantially harmed. We are early in our development efforts. Each of our product candidates will require additional preclinical and/or clinical development, regulatory approval, obtaining manufacturing supply, capacity and expertise, building a commercial organization or successfully outsourcing commercialization, substantial investment and significant marketing efforts before we generate any revenue from product sales. Our assumptions about the development potential of SION-719and SION-451are based entirely on the data generated from our ongoing Phase 1 clinical trials of SION-719 and SION-451 in healthy subjects and from preclinical studies. We have not, as a company, completed any clinical trials of our product candidates in any CF patients to date. We may also observe materially and adversely different safety results as we continue to conduct our clinical trials. Our product candidates will require substantial additional investment, clinical development, regulatory review, approval in one or more jurisdictions and significant marketing efforts before we could generate any revenue from product sales, if ever. Given our early stage of development, it will take several years before we can demonstrate the safety and efficacy of a product candidate sufficient to warrant approval for commercialization, if we