CG Oncology has reported preliminary data from the Phase II CORE1 clinical trial of its CG0070 along with Merck’s (MSD) Keytruda (pembrolizumab) to treat individuals with non-muscle-invasive bladder cancer (NMIBC) who are unresponsive to Bacillus Calmette-Guerin (BCG).

A selective oncolytic immunotherapy, CG0070 is based on an improved adenovirus type 5 backbone that has a cancer-selective promoter and a GM-CSF transgene.

The drug can potentially multiply inside tumour cells with damaged Rb pathways, leading to the disintegration of tumour cells and immunogenic cell death.

Tumour-derived antigens and GM-CSF are released when cancer cells burst, triggering a systemic anti-tumour immune response.

As part of a clinical partnership between CG Oncology and Merck, the trial enrolling up to 35 subjects analysed the safety and efficacy of the combination therapy for treating BCG-unresponsive NMIBC.

The preliminary findings demonstrated that CG0070 plus pembrolizumab was well tolerated and offered early efficacy data that was found to be favourable in nine subjects.

Furthermore, all the subjects evaluable for efficacy were found to have attained complete response (CR) at the preliminary three-month timepoint.

Of the subjects attaining further timepoints, 100% continued to show a CR through six-month and nine-month analyses.

Urinary frequency, weariness, spasm in the bladder, chills, blood discharge, autoimmune thyroiditis dysuria and flu-like symptoms were the immune-related adverse events (AEs) reported in the trial.

CG Oncology Arthur Kuan said: “We are excited to announce these preliminary results toward CG0070’s safety, tolerability and clinical efficacy in patients with bladder cancer unresponsive to BCG who have limited treatment options.

“We hope to see continued responses as the study progresses, as CG0070’s dual mechanism of action has shown to be highly effective in this difficult-to-treat patient population.”