A US Safety Review Committee (SRC) has granted unanimous approval for TransCode Therapeutics to open the fourth cohort in its Phase I trial of TTX-MC138 for treating several metastatic cancers.

This decision follows the committee’s ‘favourable’ safety data review of cohort three.

Subjects in the fourth cohort will receive a dose nearly 50% higher than the previous cohort, adhering to the original clinical protocol.

They will continue in the study, provided there are no safety concerns or disease progression.

Out of nine therapy-treated subjects, six remain under treatment, with the longest-standing subject having received seven doses nearly 28 days apart for more than seven months.

The Phase I multicentre trial involves dose-escalation and dose-expansion stages for generating data on the tolerability and safety of TTX-MC138 in patients with various metastatic solid cancers.

Although not an endpoint, the trial may also offer preliminary evidence of the clinical activity of the therapy.

The initial dose-escalation stage aims to assess the tolerability and safety of increasing therapy doses while the subsequent dose-expansion stage will further evaluate its tolerability, anti-tumour activity and safety in selected tumour types, based on the dose-escalation outcomes.

The SRC has also granted approval for the enrolment of more subjects in cohort three to enhance the safety profile of the therapy.

Analysis of data from the first two cohorts for pharmacodynamic (PD) and pharmacokinetic (PK) activity is under way, indicating that the therapy exhibits a PK/PD profile in line with preclinical findings and outcomes from the company’s Phase 0 trial.

The therapy is said to target microRNA-10b, which is said to contribute to metastatic disease progression.

TransCode Therapeutics Operations senior vice-president Sue Duggan said: “SRC approval to open the fourth cohort and expand enrolment in Cohort 3 is an important advancement for the clinical trial. It will provide an opportunity to obtain additional safety and PK/PD data, inform the dose expansion stage of the clinical trial, and may allow us to obtain initial evidence of clinical activity.”

In August 2023, TransCode dosed the first subject in the Phase 0 trial of TTX-MC138 for treating advanced solid tumours.