(Sharecast News) - Biotherapeutic pharmaceutical company 4D Pharma announced progress on activities in its development programme for its lead immuno-oncology single strain 'live biotherapeutic' candidate MRx0518 on Wednesday.

The AIM-traded firm said MRx0518 was in an ongoing phase 1 and 2 clinical trial in combination with immune checkpoint inhibitor 'Keytruda', or pembrolizumab, which is an anti-PD-1 therapy developed by MSD, in patients with advanced malignancies who had previously progressed on immune checkpoint inhibitor therapy.

It said the study consisted of two parts, with the first being an initial safety phase assessing dose-limiting toxicities of the combination, and second cohort expansion phase to assess clinical benefit in addition to safety.

In May, the successful completion of the first part, and initiation of the second, was announced.

4D Pharma said 24 additional patients across five active US sites had now been treated in the second part of the ongoing study.

The safety review following the first cohort of 10 renal cell carcinoma patients had been completed, indicating no dose-limiting toxicities.

A total of 12 patients with renal cell carcinoma, nine patients with non-small cell lung cancer, and three bladder cancer patients had been enrolled in the second part to date.

Recruitment would continue up to a total of 30 patients in each of the indications.

Target tumor reductions in patients had been observed as patients reached the first scheduled restaging time point of nine weeks.

Those included the first signals of anti-tumour activity for the combination in bladder cancer, adding to the previously-reported activity in renal cell carcinoma and non-small cell lung cancer in patients in the first part.

Three patients in the first part with renal cell carcinoma and non-small cell lung cancer that were previously reported to have experienced clinical benefit were continuing on the study, the firm said.

Two of those patients had now been treated for over 18 months, and had further target tumour reductions or extended disease control since the last update.

Efficacy of the combination was continuing to be evaluated on an ongoing basis.

"Following the positive results of part A in renal cell carcinoma and non-small cell lung cancer, the new tumour cohorts added to part B of the study are now open to recruitment," the board said in its statement.

"Patients with advanced malignancies resistant to immune checkpoint inhibitor therapy, including triple-negative breast cancer, head and neck squamous cell carcinoma and microsatellite instability-high or mismatch repair deficient cancers, are now eligible for inclusion."

Enrolment for the trial was expected to be complete in the fourth quarter of 2021.

Additionally, 4D said five patients were now enrolled in the phase 1 trial of MRx0518 with radiation in pancreatic cancer.

The company said the study was designed to evaluate safety and efficacy in 15 patients receiving treatment with MRx0518 and hypofractionated radiation, prior to surgery.

It said the study would generate "valuable data" to assess the relationship between systemic and tumour biomarkers, as well as clinical outcomes.

Study treatment was "well-tolerated" to date, with enrolment continuing and the firm expecting to receive initial data from the clinical trial in 2021.

Finally, on the trial of MRx0518 in neoadjuvant setting monotherapy, the company said the previously-reported 17 patients in the completed first part of the phase 1 study were continuing in the follow-up phase for survival outcomes.

Biomarker and safety data from the study were presented at the Society for Immunotherapy of Cancer 2020 annual meeting, demonstrating systemic immune and tumour microenvironment modulation following two-to-four weeks of treatment with MRx0518.

Additional biomarker analyses were underway to further investigate the immune response induced by MRx0518.

Those additional results could inform an optimisation of the second part of the study, the board said.

"4D Pharma has continued to make excellent progress with the MRx0518 development program on multiple fronts," said chief scientific officer Dr Alex Stevenson.

"We have generated additional safety and efficacy data, building on the positive data from both the monotherapy and Keytruda combination studies last year.

"This clinical and development progress has been achieved in spite of the headwinds of Covid-19."

Dr Stevenson said that, as 4D extended its position in the "exciting and rapidly-maturing" field, it saw the next 12 months as being "instrumental" for the space.

"We look forward to generating more clinical data from our ongoing studies of MRx0518 in multiple different tumor types and treatment settings.

"This will support 4D Pharma's continued productive engagement with regulatory authorities to develop the clinical strategy to bring this novel therapeutic to patients suffering from a range of cancers."

At 1313 GMT, shares in 4D Pharma were up 3.22% at 119.22p.