Alex Stevenson, PhD, 4D Pharma plc, Leeds, UK, shares the latest updates on trials of the single strain live biotherapeutic, MRx0518, recently presented at SITC 2020. Dr Stevenson discusses a trial of MRx0518 in combination with pembrolizumab, an immune checkpoint inhibitor, in patients with secondary resistance to pembrolizumab, in the hopes of reactivating the antitumor efficacy of anti-PD-1 therapy with MRx0518. Part A of the study is complete with evidence of clinical benefit and durable responses in patients, in addition to a very promising safety profile. To date, part B is in the enrolment stage, with greater patient numbers and more varied tumor types than part A. Dr Stevenson also discusses a new neoadjuvant biomarker study using MRx0518 monotherapy in patients with newly diagnosed patients with solid tumors. By treating patients prior to tumor resection, it is hoped that biopsy and tumor samples can be compared from before and after treatment, to improve understanding of the treatment’s mechanism of action. Data is encouraging so far, with reports of increased immune infiltration and changes in tumor gene expression. This interview was recorded via an online conference call with The Video Journal of Oncology (VJOncology).