Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 29

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 29
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izer 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 and with an approved product may subject us to risks that we would not face if our product candidates were being developed to be
administered as a monotherapy.

For example, either the combination of our product candidates with each other, or our NBD1 stabilizer with the
standard of care, may result in adverse side effects or toxicities that the product candidates or other therapy do not produce when used alone. In addition, the product candidates may interact with each other, or with the approved product, in
undesirable ways that could negatively impact the efficacy of our product candidates, any components of the approved product, or the combination as a whole. Testing product candidates in combination with each other and with an approved therapy may
increase the risk of significant adverse effects or failed clinical trials. The timing, outcome and cost of developing products to be used in combination with other therapies is difficult to predict and dependent on a number of factors that are
outside our reasonable control.

In addition, to the extent we choose to develop a product candidate for use in combination with an approved
therapy, the FDA or comparable foreign regulatory authorities could revoke approval of, or that safety, efficacy, manufacturing or supply issues could arise with, the therapy used in combination with our product candidate. If the therapies we use in
combination with our product candidates are replaced as the standard of care, the FDA or comparable foreign regulatory authorities may require us to conduct additional clinical trials, or we may not be able to obtain adequate reimbursement from
third-party payors. The occurrence of