4D Pharma has reported initial data from an ongoing Phase I/II clinical trial of a combination of its MRx0518 with MSD’s Keytruda in various cancer types.

The trial enrolled renal cell carcinoma (RCC), melanoma, non-small cell lung cancer (NSCLC) and bladder cancer patients who have previously responded and then progressed on PD-1/PD-L1 inhibitors.

Keytruda is an anti-PD-1 therapy, while MRx0518 is a single strain live biotherapeutic designed to induce the body’s immune system to attack cancer cells.

The open-label, two-part Phase I/II trial is evaluating the safety and preliminary efficacy of the combination in up to 132 patients.

Participants receive intravenous Keytruda every three weeks and one MRx0518 capsule twice daily.

According to preliminary data from six patients, the combination was well-tolerated and demonstrated a clinically relevant response in two subjects with prior progressive disease.

One additional subject showed stable disease. 4D pharma added that three patients discontinued the study due to disease-related reasons. Data did not reveal any drug-related serious adverse events.

4D pharma chief scientific officer Dr Alex Stevenson said: “Although more work will be required to establish the robustness of the responses observed and their frequency in a larger number of patients, we are pleased to be able to report these initial results, the first from an oncology study involving a live biotherapeutic product.

“The open-label study is ongoing and we will be reviewing data on a continual basis to optimise our future development strategy for MRx0518 in these indications.”

MRx0518 is also being assessed as a monotherapy in a Phase I trial involving patients with solid tumours at Imperial College London in the UK.

The company is planning to further study the drug candidate in other cancer types and settings, including a combination with radiotherapy in pancreatic cancer patients at MD Anderson, US.