Eton Pharmaceuticals, Inc.

Item 1.01: Entry into a Material Definitive Agreement On July 31, 2026, Eton Pharmaceuticals, Inc. (“Eton” or the “Company”) entered into a license agreement (the "Agreement") for a late-stage rare disease product candidate ASN-001 (timolol topical gel) from Auson Pharmaceuticals Inc. ("Auson") for the treatment of proliferating superficial infantile hemangiomas. Under the terms of the Agreement, the Company will pay an upfront license fee to Auson of $3.0 million within thirty days of the Agreement. Additionally, the Company will run a bioavailability bridging study for ASN-001 and, if successful, intends to submit the New Drug Application (NDA) upon completion of the study in the second half of 2027. Upon the successful approval of ASN-001 by the U.S. Food and Drug Administration ("FDA"), the Company would be responsible for the following milestone payments: $5,000,000 upon first commercial sale of product after FDA approval. $1,000,000 upon first calendar year in which aggregate annual net sales of product meet or exceed $20,000,000. $2,500,000 upon first calendar year in which aggregate annual net sales of product meet or exceed $40,000,000. $5,000,000 upon first calendar year in which aggregate annual net sales of product meet or exceed $80,000,000. $10,000,000 upon first calendar year in which aggregate annual net sales of product meet or exceed $150,000,000. $10,000,000 upon first calendar year in which aggregate annual net sales of product meet or exceed $280,000,000. The Company would pay tiered royalties to Auson as follows: 10% royalty rate for net product sales of less than or equal to $200,000,000; 13% royalty rate for net product sales greater than $200,000,000 but less than or equal to $400,000,000 and 15% royalty rate for net product sales greater than $400,000,000. The royalty tiers are based on cumulative lifetime product sales. A copy of the press release announcing the transaction dated August 5, 2026 is attached as Exhibit 99.1 to this Current Report on Form 8-K. Item 2.01: Completion of Acquisition or Disposition of Assets As disclosed in Item 1.01, on July 31, 2026, the Company entered into a license agreement for a late-stage rare disease product candidate, ASN-001 (timolol topical gel), from Auson for the treatment of proliferating superficial infantile hemangiomas. The information in Item 1.01 is hereby incorporated by reference into this Item 2.01.