IDEAYA Biosciences Grants Inducement Stock Options to New Employees under Nasdaq Listing Rule 5635(c)(4)

SOUTH SAN FRANCISCO, Calif., July 31, 2026 — IDEAYA Biosciences, Inc. (NASDAQ: IDYA), a leading precision medicine oncology company dedicated to discovering and developing targeted therapeutics, has announced equity awards for incoming talent.

On July 30, 2026, the Compensation Committee of IDEAYA's Board of Directors awarded non-qualified stock options to purchase an aggregate of 260,200 shares of the company's common stock to fourteen newly hired employees.

Details of the Inducement Grants

The equity awards were issued under the IDEAYA Biosciences, Inc. 2023 Employment Inducement Incentive Award Plan (2023 Inducement Plan). In accordance with Nasdaq Listing Rule 5635(c)(4), these grants serve as an essential material inducement for these individuals entering into employment with IDEAYA.

• Eligibility: The 2023 Inducement Plan is utilized exclusively for granting equity awards to individuals who were not previously employees of IDEAYA (or following a bona fide period of non-employment) as an inducement to join the company.
• Exercise Price: The stock options feature an exercise price of $36.40 per share, matching the closing price of IDEAYA's common stock on The Nasdaq Global Select Market on the grant date (July 30, 2026).

• Term and Vesting Schedule:

• The options carry a 10-year term.
• They will vest over a four-year period, with 25% of the options vesting on the first anniversary of the vesting commencement date.
• The remaining 75% will vest in equal monthly installments over the subsequent three years.
• All vesting remains strictly subject to each employee's continued service to IDEAYA on each applicable vesting date.