Microbiotica reveals novel mechanisms

Cambridge, UK – 29 April 2025: Microbiotica, a clinical-stage biopharma company developing a pipeline of oral precision microbiome medicines called live biotherapeutic products (LBPs), has presented new data on the mechanism of action of MB097 at the American Association for Cancer Research (AACR) annual meeting held in Chicago, April 25-30. MB097 is an LBP in development as a co-therapy for immune checkpoint inhibitors (CPI) such as MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy, KEYTRUDA® (pembrolizumab).

The composition of a patient’s intestinal microbiome is known to impact the response to immunotherapies, most noticeably CPI, but the mechanisms are poorly understood. MB097 comprises nine different species of gut commensal bacteria, all linked to positive CPI response in multiple clinical studies. Microbiotica has developed in vitro human systems using primary immune cells to investigate how gut bacteria modulate the immune response to cancer. These assays have demonstrated that three of the MB097 strains induce dendritic cells to produce high levels of IL-12, which in turn stimulates Cytotoxic T Lymphocytes and NK cells with potent tumour cell killing activity. Dr Mat Robinson, Microbiotica’s Senior Vice-President Research, presented these novel findings in a poster entitled ‘Clinical response to immune checkpoint inhibitors in melanoma is associated with distinct gut bacterial species that promote anti-tumour immunity by different mechanisms’. The poster can be accessed here.

Dr Mat Robinson, Microbiotica’s SVP Research, said :

These exciting results start to unravel the complex biology of how gut commensal bacteria drive immune checkpoint inhibitor responses. The induction of dendritic cells to produce IL-12 complement the recently reported data showing that other MB097 strains release metabolites that enhance immune-mediated cancer cell killing. Together, these findings demonstrate that the different strains within MB097 can interact with the immune system of cancer patients in multiple ways to enhance immunotherapy efficacy.

MB097 is being tested in an international Phase 1b clinical study, in combination with KEYTRUDA® (pembrolizumab), MSD's anti-PD-1 therapy, in patients with cutaneous melanoma who have failed to respond to immunotherapies. Data readout is expected by the end of 2025.