Precision medicine oncology company IDEAYA Biosciences Inc (NASDAQ: IDYA) disclosed on Monday that it has enrolled the first patient in a Phase 1 clinical trial evaluating IDE892, an investigational PRMT5 inhibitor being developed for MTAP-deleted solid tumours, including non-small cell lung cancer and pancreatic ductal adenocarcinoma.

The study will assess the safety, tolerability, pharmacokinetics and pharmacodynamics of IDE892 as a monotherapy treatment. The company also plans to evaluate the drug in combination with IDE397, its MAT2A inhibitor, with a combination first-patient-in targeted for mid-2026. Preclinical studies have shown durable tumour regressions in MTAP-deleted models using the dual inhibition approach.

IDE892 has been designed as a potential best-in-class PRMT5 inhibitor, demonstrating around 1,400-fold selective binding to MTA-PRMT5 complexes and single-digit nanomolar potency in MTAP-deleted cell lines. The drug has also shown tumour regressions in preclinical models as a monotherapy and durable complete responses when combined with IDE397.

Separately, IDEAYA Biosciences said it is advancing its CDKN2A-deficiency programme, with plans to nominate a development candidate in the second half of 2026 and submit an investigational new drug application in the first half of 2027. CDKN2A deficiency occurs in a significant proportion of cancers, including more than 80% of pancreatic cancer cases.

As part of a strategic focus on its proprietary MTAP-deleted and CDKN2A pipeline, the company will deprioritise combination activities with Trodelvy and conclude enrolment in ongoing Phase 1/2 trials conducted with Gilead Sciences Inc.

MTAP deletion is estimated to occur in 15–20% of non-small cell lung cancer cases, up to 40% of pancreatic cancer and around 15% of all solid tumours, with no approved targeted therapies currently available for these patients.