Material Event (Form 8-K)

On October 14, 2026, Coya Therapeutics, Inc. (the "Company") issued a press release announcing plans to initiate an open-label extension ("OLE") of the Phase 2/3 ALSTARS Trial (NCT07161999) evaluating COYA 302 for the treatment of amyotrophic lateral sclerosis ("ALS"). The Company plans to initiate the OLE in response to requests from ALSTARS investigators and study participants. The OLE will provide participants who complete the 48-week treatment period with the opportunity to continue receiving COYA 302, while enabling the collection of longer-term efficacy and safety data. The Company expects the OLE to begin in November 2026 as the first cohort completes the 48-week treatment period.

Concurrent with the anticipated initiation of the OLE, the Company expects to prioritize resources toward the ongoing clinical development of COYA 302 in ALS and assuring timely completion of important near-term milestones in the ALSTARS Trial. With this prioritization, the planned initiation of the Phase 2 clinical trial evaluating COYA 302 in frontotemporal dementia ("FTD"), previously anticipated in the second half of 2026, is now expected in 2027.

The Company's cash runway guidance remains unchanged, with existing cash resources expected to fund operations into the second half of 2027, beyond the anticipated ALSTARS topline data readout.

The ALSTARS Trial is a Phase 2/3, randomized, multi-center, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of COYA 302 in patients with ALS. Approximately 120 subjects will be randomized 1:1:1 to receive one of two pre-specified dosing regimens of COYA 302 or placebo during a 24-week double-blind treatment phase. Patients who complete the 24-week placebo-controlled phase enter a 24-week blinded active-treatment extension phase; patients receiving COYA 302 continue their assigned regimen, while placebo patients are re-randomized to one of the two COYA 302 dosing regimens, providing up to 48 weeks of data on COYA 302. The primary endpoint is change in disease severity over time, measured by the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) total score from baseline to Week 24 compared with placebo. Study objectives include evaluation of efficacy, safety and tolerability, biological activity, and biomarker levels.