Company: SION
Filing Date: 2025-01-17
Form Type: S-1
Source: 0001193125-25-008474
Chunk: 12

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-01-17
Form: S-1
Chunk 12
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 of the FDA and comparable foreign authorities are lengthy, time-consuming and inherently                         
 unpredictable. If we are not able to obtain the required regulatory approval for any product candidate, our business will be substantially harmed. |

| • |     | We have not yet completed all testing of any product candidate in clinical trials. Preclinical, interim, topline and                                                                                                                                    
 preliminary results from our preclinical studies or clinical trials are not necessarily predictive of the results or analyses of such results of later clinical trials. If we cannot replicate the positive results from any preclinical studies or     
 clinical trials of our current or potential future product candidates that have positive results, or if we suffer any other significant setbacks in our later clinical trials, we may be unable to successfully develop, obtain regulatory approval for 
 and commercialize our current or potential future product candidates.                                                                                                                                                                                   |

| • |     | Targeting the NBD1 domain of the CFTR protein is novel, and we do not know whether we will be able to successfully develop 
 any products.                                                                                                              |

| • |     | Our preclinical studies and clinical trials may fail to demonstrate the safety and efficacy of our product candidates, or                                                                                                                                 
 serious or unacceptable adverse side effects or unexpected toxicology findings may be identified during the development of our product candidates, which could prevent or delay further clinical development, regulatory approvals and commercialization, 
 impact the product’s labeling, if approved, increase our costs or necessitate the abandonment or limitation of the development of some of our product candidates.                                                                                         |

| • |     | We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on 
 product candidates or indications that may be more profitable or for which there is a greater likelihood of success. |

| • |     | We are dependent on licensed intellectual property. If we were to lose our rights to licensed intellectual property, we may                                                                                                                             
 not be able to continue developing or commercializing our product candidates, if approved. If we breach any of the agreements under which we license the use, development and commercialization rights to our product candidates from third parties or, 
 in certain cases, we fail to meet certain development deadlines, we could lose license rights that are important to our business.                                                                                                                       |

| • |     | We contract with third parties for the manufacture of our product candidates for clinical drug supply and expect to                                                                                                                                  
 continue to do so for commercialization, if our product candidates are approved. This reliance on third parties increases the risk that we will not have sufficient quantities of our