4D pharma plc (LON:DDDD) has unveiled new positive clinical data from two trials of MRx0518, its lead immuno-oncology single strain Live Biotherapeutic candidate. 

The data is presented in three posters at the Society for Immunotherapy of Cancer Annual Meeting 2020, happening this week.

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The first poster includes the first data presented for MRx0518 as a monotherapy, the firm said, and the results are from the completed Part A of a Phase I trial of MRx0518 in the neoadjuvant setting.

Two further presentations provide updates on the ongoing Phase I/II trial of MRx0518 in combination with Merck’s Keytruda (pembrolizumab) in patients that cannot manage checkpoint inhibitors.

MRx0518 in Neoadjuvant Setting Monotherapy

The ongoing, two-part Phase I study is assessing the safety and tolerability of MRx0518 monotherapy in subjects undergoing surgical removal of solid tumours who never received treatment.

The study is designed to generate paired patient samples at diagnostic biopsy and surgical removal, with an intervening period of MRx0518 monotherapy treatment of two to four weeks.

The candidate was well-tolerated and gene expression analysis identified significant expression changes in 98 genes.

MRx0518 in Combination with Pembrolizumab

The candidate is also being assessed in a Phase I/II open-label, two-part clinical trial to evaluate its safety and preliminary efficacy in combination with pembrolizumab in heavily pre-treated metastatic patients with solid tumors refractory to immune checkpoint inhibitors.

The part A is for patients with metastatic renal cell carcinoma (RCC) and non-small cell lung cancer (NSCLC), while in the part B the firm is currently enrolling up to 120 patients with RCC, NSCLC, bladder cancer, triple-negative breast cancer, head and neck squamous cell carcinoma and microsatellite instability-high/mismatch repair deficient solid tumours.

Enrollment is expected to complete in the fourth quarter of 2021.

In the part A of the study, MRx0518 provided clinical benefit to 42% of patients and was generally well-tolerated.

Chief executive Duncan Peyton said this data is further evidence of the potential of 4D’s live biotherapeutics in oncology.

“The strong immunological signals of biological activity shown in the monotherapy trial provides further clinical evidence of the role and contribution of MRx0518 to the impressive results we are seeing in combination with Keytruda in an incredibly difficult to treat patient population,” he said in an update.

“The data also furthers and clarifies our earlier work on the mechanism of action of MRx0518 and, importantly, the activity we are seeing in these patients mirrors the preclinical results, further validating our approach and the MicroRx platform.” 

“The data generated from these trials provide us with huge confidence not only with moving forward with MRx0518 as a novel immunotherapy for the treatment of cancer, but also our MicroRx platform,” Peyton added.

“We look forward to advancing our MRx0518 program further into the clinic and we are already enrolling patients into Part B of our Keytruda combination study, including the addition of new tumor type cohorts.”