US-based biotechnology company Ideaya Biosciences has selected a monotherapy expansion dose for a Phase II trial assessing IDE397.

The trial is evaluating IDE397's ability to treat patients with solid tumours that have methylthioadenosine phosphorylase (MTAP) deletion.

IDEAYA has selected a dose for evaluating IDE397's efficacy against high-priority, MTAP-deletion solid tumour types, including non-small cell lung cancer (NSCLC), bladder cancer and gastroesophageal cancers.

It is estimated that MTAP deletion happens in around 16% of NSCLC cases, nearly 30% of bladder cancer cases and roughly 15%-25% of gastroesophageal cancer cases.

These indications are being prioritised based on preliminary clinical efficacy and preclinical data that show in vivo efficacy in related patient-derived and/or cell-derived xenograft models, as well as endogenous pathway suppression in MTAP-deleted tumours.

IDE397 is a potent and selective small molecule inhibitor targeting methionine adenosyltransferase 2a (MAT2A).

The drug is currently being studied as a single agent in a Phase I/II trial to treat patients with solid tumours that have MTAP deletion.

Enrolment for a global Phase II trial of the therapy is also underway.

IDEAYA Biosciences chief medical officer Dr Darrin Beaupre said: “We have selected a IDE397 Phase II monotherapy expansion dose for evaluation in our high-priority solid tumour types with MTAP deletion, including NSCLC, bladder cancer and gastroesophageal cancer. 

“We are in the early stages of enrolment into our global Phase II clinical trial monotherapy expansion and have clinical objectives to further define IDE397's monotherapy efficacy in our high-priority solid tumour types and to address the contribution of components for clinical combinations.”

In addition, IDEAYA has partnered with Amgen to examine the combination of IDE397 and AMG 193 to treat patients with solid tumours that have MTAP deletion. 

Last month, the US Food and Drug Administration authorised the companies to begin a Phase I/II trial of IDE397 in combination with AMG 193.