Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 132

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 132
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 on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our
operations.

As of September 30, 2024, we had cash, cash equivalents and marketable securities of $180.9 million. Based upon our current
operating plans, we believe that the estimated net proceeds from this offering, together with our existing cash, cash equivalents and investments in marketable securities, will be sufficient to fund our operations into 2028. We have based this
estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. In addition, we could utilize our available capital resources sooner than we expect. See the sections titled
“—Liquidity and Capital Resources” and “Risk Factors—Risks Related to Our Limited Operating History, Financial Condition and Need for Additional Capital” included elsewhere in this prospectus. We believe
that we will have sufficient funds to meet our obligations within the next twelve months after the date that our condensed consolidated financial statements included in this prospectus are issued. See the section titled “Use of Proceeds.”

License and Collaboration Agreements

Below is a summary of the key terms for certain of our license and collaboration agreements. For a more detailed description of these agreements, see the
section titled “Business—License and Collaboration Agreements.”

Sanofi License Agreement

In December 2019, we entered into a license agreement, which has been subsequently amended (as amended, the “Sanofi License Agreement”), with
Sanofi, pursuant to which we have been granted an exclusive, worldwide, sublicensable, royalty-bearing license to develop and commercialize products using the licensed compounds and know-how for CFTR modulator
therapies. The licensed and derived rights are being utilized in SION-719, SION-109 and SION-451.

As initial consideration for the license, we paid a non-refundable, upfront payment of $1.5 million, as
well as a reimbursement of $0.3 million for Sanofi’s research and development expenses, which was recorded as research and development expense in the condensed consolidated statements of operations and comprehensive loss because the
acquired license represented in-process research and development with no alternative future use. In addition, we are required to pay Sanofi a total of up to $40.0 million upon achievement of certain
late-stage developmental and commercial milestones. The developmental milestone payment will be recorded when the milestone is achieved, and the