SOLIGENIX, INC.

As previously reported in the Company’s Current Report on Form 8-K filed on April 28, 2026, the Data Monitoring Committee (the “DMC”) completed an interim efficacy analysis of the Company’s confirmatory Phase 3 FLASH2 (Fluorescent Light Activated Synthetic Hypericin 2) clinical trial evaluating HyBryte™ (synthetic hypericin) for the treatment of cutaneous T-cell lymphoma and recommended that the study be halted for futility. Following a thorough

review of the DMC’s recommendation and evaluation of the program’s path forward, on June 11, 2026, the Company’s Board of Directors determined that it is in the best interest of the Company and its stockholders to terminate the HyBryte™ development program.

The Company will undertake an orderly wind-down of the FLASH2 trial and related HyBryte™ development activities. The Company estimates that it will incur approximately $70,000 in charges in connection with the wind-down of the HyBryte™ program, consisting primarily of clinical trial close-out costs and related expenses.

The Company intends to continue to evaluate all strategic options moving forward, including but not limited to merger and acquisition opportunities, as well as the potential of advancing its other pipeline programs, including dusquetide (SGX945) for the treatment of Behçet’s Disease, which has received orphan drug designation from the U.S. Food and Drug Administration, orphan drug designation from the European Commission, and Promising Innovative Medicine designation from the UK Medicines and Healthcare products Regulatory Agency.