US-based biotechnology company Ideaya Biosciences has reported positive interim data from a Phase II trial of IDE397 to treat methylthioadenosine phosphorylase (MTAP) deletion urothelial and non-small cell lung cancer (NSCLC).

The study evaluated a 30mg once-daily dose of IDE397 in 18 evaluable patients, who included individuals with urothelial cancer, adenocarcinoma NSCLC and squamous NSCLC.

Preliminary results indicate an overall response rate of 39% and disease control rate of 94%, with 78% of patients experiencing tumour shrinkage.

The reported clinical efficacy and tolerability data are preliminary and based on an investigator review from an unlocked database as of 21 June.

The RECIST 1.1 evaluation showed one complete response and six partial responses out of the 18 evaluable patients.

In addition, the trial saw a circulating tumour DNA molecular response rate of 81% among patients.

Its swim lane plot by CT-scan evaluation and initial durability assessment showed that 11 patients are still on treatment, with five maintaining their RECIST 1.1 response.

The treatment showed a favourable adverse event profile with no drug-related serious adverse events observed at IDE397 30mg once-a-day expansion dose.

IDEAYA Biosciences chief medical officer Dr Darrin Beaupre said: “We are highly encouraged by the preliminary clinical efficacy and favourable safety profile observed with IDE397 at the 30mg once-a-day expansion dose, including multiple partial responses and one complete response by RECIST 1.1 in MTAP-deletion urothelial and lung cancer patients.

“In addition, at this expansion dose, we observed a favourable adverse event profile with no drug-related serious adverse events and mid-single digit percent Grade III or higher drug-related adverse events, which we believe has the potential to enable longer duration dosing as well as combinations.”

Last month, IDEAYA dosed the first subject in its Phase I trial of IDE397 plus Trodelvy in patients with MTAP-deletion bladder cancer.