Material Event (Form 8-K)

On September 24, 2025, Cidara Therapeutics, Inc. (the "Company") announced updates to its planned Phase 3 registrational trial of CD388 following its End-of-Phase2 meeting with the U.S. Food and Drug Administration (the "FDA"). The Company is proceeding with an expanded and accelerated development plan seeking biologics license application ("BLA") approval based on a single Phase 3 study. Based on FDA feedback the study population will be expanded to include adults over 65 years of age with no specific co-morbiditiesin addition to subjects over 12 years of age with high-risk comorbidities or immune compromised status, substantially increasing the initial number of patients potentially eligible to receive CD388 from approximately 50 million to well over 100 million people in the United States.

The planned Phase 3 study will be a global, multicenter, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of a single 450-milligramdose of CD388 administered via subcutaneous injection at the beginning of the flu season. The Company intends to begin enrollment by the end of September 2025 in the Northern Hemisphere with continuation into the spring of 2026 in the Southern Hemisphere, with a target enrollment of 6,000 subjects. This represents a six-monthacceleration from the prior plan to initiate the Phase 3 study in the spring of 2026 in the Southern Hemisphere. The study will include an interim analysis following the Northern Hemisphere flu season, to assess the trial size and powering assumptions and determine enrollment for the Southern Hemisphere flu season.

The Company believes that its existing cash, cash equivalents and restricted cash will be sufficient to fully fund its planned Phase 3 development program through completion.

In the Company's planned Phase 3 study, participants will be randomized in a 1:1 ratio to receive either a 450-milligramdose of CD388 or placebo. The primary endpoint will be based on laboratory-confirmed influenza, body temperature ≥ 37.2°C (99°F), and new or worsening of either two respiratory symptoms (cough, sore throat, nasal congestion) or one respiratory symptom and one new systemic symptom (headache, fatigue, feeling feverish, or body aches).