Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 133

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 133
---
 commercial milestone payment and royalties will be recorded when the sales occur. As of
September 30, 2024, none of such milestones have been achieved. We are also required to pay royalties to Sanofi in the low single-digit percentage range based on net sales of licensed products, subject to customary reductions and offsets. Such
royalty payments shall be reduced for products covered by derived patents.

96

CFF Payment Agreement

In December 2019, we entered into a payment agreement (the “CFF Payment Agreement”) with CFF, pursuant to which we agreed to provide CFF with
compensation in exchange for the grant of, or forbearance from exercising, certain of CFF’s rights existing under the license agreement, by and between CFF (through an assignment by Cystic Fibrosis Foundation Therapeutics, Inc.) and Genzyme
Corporation, an affiliate of Sanofi (the “CFFT-Genzyme Agreement”). Under the CFF Payment Agreement, we are obligated to compensate CFF in connection with our development and commercialization of
licensed products under the Sanofi License Agreement.

As initial consideration for CFF’s grant of, and forbearance from exercising, its rights
under the CFFT-Genzyme Agreement, we paid an upfront fee of $0.2 million and issued CFF 300,300 shares of our Series Seed preferred stock, valued at $1.0 million. In addition, we agreed to pay CFF a sub-teen double-digit percentage of any amounts paid by us to Sanofi under the Sanofi License Agreement, other than milestone, royalty or reimbursement payments. We are required to pay CFF 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 commercial milestone payment and royalties will be
recorded when the sales occur. As of September 30, 2024, none of such milestones have been achieved. We are also required to pay revenue-shares of royalty payments to CFF in the low single-digit percentage range based on net sales of licensed
products, subject to customary reductions and offsets. Such milestone and royalty payments shall be reduced for products covered by derived patents. Further, a side letter was executed between us and Sanofi, which clarifies the relationship between
us, Sanofi and CFF, under which we are obligated to pay Sanofi 20% of the milestones it would have been obligated