Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 85

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 85
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 of a proprietary combination therapy;                                   |

| • |     | the prevalence and severity of any side effects; |

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| • |     | our ability to offer our products at competitive prices; |

| • |     | the convenience and ease of administration compared to alternative treatments; |

| • |     | product labeling or product insert requirements of the FDA or comparable foreign regulatory authorities, including any 
 limitations or warnings contained in a product’s approved labeling, including any boxed warning;                       |

| • |     | the product’s acceptance into current standard of care treatment algorithms by medical societies that could affect 
 payor and physician uptake;                                                                                        |

| • |     | the effectiveness of sales and marketing efforts, and the strength of sales, marketing and distribution support; |

| • |     | the availability of third-party coverage and adequate reimbursement for any product candidates, once approved; |

| • |     | the willingness of the target patient population to try, and of physicians to prescribe, the product; |

| • |     | any restrictions on the use of our products together with other medications; and |

| • |     | potential product liability claims and unfavorable publicity related to our products. |

Any failure by one or more of our product candidates that obtains regulatory approvals to achieve market acceptance or commercial success would adversely affect our business prospects. Due to the significant resources required for the development of our pipeline, and depending on our ability to access capital, we must prioritize the development of certain product candidates over others. Moreover, we may fail to expend our limited resources on product candidates or indications that may have been more profitable or for which there is a greater likelihood of success. Due to the significant resources required for the development of our product candidates, we must decide which product candidates and indications to pursue and advance and the amount of resources to allocate to each. Our decisions concerning the allocation of research, development, collaboration, management and financial resources toward particular product candidates, therapeutic areas or indications may not lead to the development of viable commercial products and may divert resources away from better opportunities. For example, we intend to select a lead NBD1 stabilizer product candidate after the completion of our ongoing Phase 1 clinical trials of SION-719and SION-451,and a lead complementary modulator product candidate from our two most advanced modulator product candidates, galicaftor and SION-109.If we make incorrect determinations regarding the viability or market potential of either lead product candidate, or any of our other current or future product candidates, or misread trends