05:16 AM EDT, 09/08/2025 (MT Newswires) -- (Updates with the stock price movement in the last paragraph.)

Ideaya Biosciences ( IDYA ) and Hengrui Pharma said Sunday that initial data from a phase 1 trial of the experimental IDE849 small cell lung cancer treatment showed strong overall response and disease control rates across all tested doses and stages of treatment, with only a modest decline in later-line patients, an expected outcome due to their more advanced disease.

The company said that in patients with brain metastases, response rates were promising, with an 83.3% overall response rate and 100% disease control at the 2.4 mg/kg dose.

Across all doses, the overall response rate in patients with baseline brain metastases was 66.7%.

The drugmaker said it holds exclusive rights to develop and commercialize IDE849 outside Greater China under a licensing agreement signed with Hengrui Pharma in December 2024.

Ideaya shares were up nearly 12% in recent premarket activity Monday.