Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 146

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 146
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 financial condition and on our ability to pursue our business plans and strategies. 106

If we are unable to raise additional funds, we may be required to delay, limit, reduce or terminate
our product development or future commercialization efforts.

Contractual Obligations and Commitments

Research and Development and Manufacturing Agreements

We
enter into contracts in the normal course of business with CROs, CDMOs and other vendors to assist in the research and development activities and other services and products for operating purposes. These contracts generally provide for termination
at any time upon a certain amount of prior notice.

Leases

In May 2022, we executed a non-cancelable operating lease in Waltham, Massachusetts (the “Waltham
Lease”) to rent out 24,051 square feet of laboratory and office space and relocated our headquarters to Waltham in January 2023. Total expected cash payments in connection with the Waltham Lease will be $9.7 million over the term of the
agreement ending in 2030. This excludes our share of facility operating expenses, real-estate taxes and other costs that are reimbursable to the landlord under the lease. For additional information regarding the lease obligations see Note 7,
“Leases” in our consolidated financial statements included elsewhere in this prospectus.

License Agreements

Our agreements with certain third parties to license intellectual property include potential milestone fees, sublicense fees and royalty fees. The
milestone fees are dependent upon the development of products using the intellectual property licensed under the arrangements and contingent upon the achievement of development or regulatory approval milestones, as well as commercial milestones.
These potential obligations are contingent upon the occurrence of future events and the timing and likelihood of such potential obligations are not known with certainty. For further information regarding these agreements, please see
“Business—Licenses and Collaboration Agreements.”

Critical Accounting Estimates

Our management’s discussion and analysis of our financial condition and results of operations are based on our consolidated financial statements,
which are prepared in accordance with GAAP. The preparation of our consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, costs and expenses and the disclosure of
contingent assets and liabilities in our consolidated financial statements and accompanying notes. We base our estimates and assumptions on historical experience and other factors that we believe to be reasonable under the circumstances. We evaluate
our estimates and judgments on an ongoing basis. We base our estimates on historical experience, known trends and events and on various