Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 27

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 27
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 can do so at all. We do not have complete control over many of these factors, including certain aspects of clinical development and the regulatory submission process, potential threats to our intellectual property rights and the manufacturing, marketing, distribution and sales efforts of any future collaborator. If we are not successful with respect to one or more of these factors in a timely manner or at all, we could experience significant delays or an inability to successfully commercialize the product candidates we develop, which would materially harm our business. If we do not receive marketing approvals for our product candidates or any future product candidate we develop or if we experience delays in such approvals, we may not be able to continue our operations. Further, conducting clinical trials in foreign countries, as we may do for our current or future product candidates, presents additional risks that may delay completion of our clinical trials. These risks include the failure of enrolled patients in foreign countries to adhere to clinical protocol as a result of differences in healthcare services or cultural customs, failure to properly translate or interpret patient-reported outcome endpoints, managing additional administrative burdens associated with foreign regulatory schemes as well as political and economic risks relevant to such foreign countries. 22

The foregoing makes our ability to successfully and timely complete development of our product
candidates and obtain regulatory approval for them less certain. If we are unable to develop, or obtain marketing approval for, or, if approved, successfully commercialize our product candidates, our business, financial condition, results of
operations and prospects could be materially harmed.

We intend to develop our lead NBD1 stabilizer product candidate to be administered in combination with one of our complementary modulators or as an add-onto the standard of care. Developing combination treatments increases complexity and risk, including risks of drug-drug interactions, unforeseen side effects or failures in our clinical trials that could delay or prevent their regulatory approval or limit the commercial profile of an approved label.

The current treatment paradigm in CF for all patients with the F508del mutation is based on a combination of drug therapies. After the completion of our
ongoing Phase 1 clinical trials of SION-719 and SION-451, we intend to select a lead NBD1 stabilizer product candidate for further development in combination with other
compounds, specifically, with one of our complementary modulator product candidates, or with the standard of care. We intend to select a lead complementary modulator candidate from our two most advanced modulator candidates, galicaftor and SION-109. The use of our product candidates in combination with each other