Atossa Therapeutics Announces Plan to Issue Stapled CVR for Shareholders Tied to Potential Rare Pediatric Disease Priority Review Voucher (Form 8-K)

Atossa Therapeutics Announces Plan to Issue Stapled CVR for Shareholders Tied to Potential Rare Pediatric Disease Priority Review Voucher

Shareholders would receive one CVR for each ATOS share held as of the record date or issued thereafter

CVRs would entitle holders to 25% of net proceeds from monetization of Atossa's first qualifying priority review voucher, subject to a $50 million aggregate payment cap

SEATTLE, September 29, 2026 - Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing innovative medicines in oncology and other areas of significant unmet need, today announced that its Board of Directors has approved a plan to issue one contingent value right ("CVR") for each share of Atossa common stock to enable shareholders to share in a portion of any proceeds received from the monetization of Atossa's first qualifying rare pediatric disease priority review voucher.

The CVR would give shareholders a contractual right to participate in the potential future value of the first qualifying FDA priority review voucher arising from an Atossa development program. Under the CVR agreement, holders would receive, in the aggregate, 25% of net proceeds from a qualifying voucher monetization event (including if a qualifying voucher is used by Atossa or held at the time of a change of control), up to a maximum aggregate payment of $50 million.

Atossa has received two FDA rare pediatric disease designations for (Z)-endoxifen, one in Duchenne muscular dystrophy and one in McCune-Albright syndrome. If a qualifying marketing application is approved within the applicable voucher program's requirements, Atossa may be awarded a priority review voucher. No Atossa product candidate has been approved, and no voucher has been awarded to date. As a result, no CVR payment is assured.

"We believe shareholders should have a direct opportunity to participate if our rare disease programs create the added value of a priority review voucher," said Steven C. Quay, M.D., Ph.D., Atossa's Chairman, President and Chief Executive Officer. "This CVR would make that commitment tangible. It links a meaningful share of any qualifying voucher proceeds to the people who own Atossa, while allowing us to continue pursuing the development opportunities for (Z)-endoxifen."

How the CVR works

Atossa has previously reported that disclosed priority review voucher sales in the preceding 18-24 months ranged from $100 million to $220 million; however, past sales do not establish the value of any voucher Atossa might receive. The CVRs relate only to the first qualifying voucher specified in the CVR agreement. They do not represent an ownership interest in a voucher or provide a separate voting or dividend right. The CVRs would expire under the terms of the CVR agreement if no qualifying voucher is awarded by December 31, 2036, unless the Board extends that date.

Atossa expects to file the CVR agreement with the Securities and Exchange Commission once executed.

About Atossa Therapeutics

Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing innovative medicines in oncology and other areas of significant unmet need. The Company's lead product candidate, (Z)-endoxifen, is in development across several clinical settings, including potential applications in oncology and rare diseases. Atossa has received FDA Orphan Drug Designation for (Z)-endoxifen for Duchenne muscular dystrophy and Rare Pediatric Disease designations for Duchenne muscular dystrophy and McCune-Albright syndrome. (Z)-endoxifen is not approved for any indication. More information is available at atossatherapeutics.com.