Microbiotica reveals novel mechanisms showing how the microbiome can improve immunotherapy response based on MB097, a clinical-stage drug candidate being evaluated in combination with KEYTRUDA® (pembrolizumab) in patients with advanced melanoma

Data presented at AACR Annual Meeting in Chicago

/EIN News/ -- CAMBRIDGE, United Kingdom, April 29, 2025 (GLOBE NEWSWIRE) -- 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.

Notes to Editors

KEYTRUDA^® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

About Melanoma – MB097 and the MELODY-1 study

Melanoma is a life-threatening skin cancer that can spread to other parts of the body in its advanced stages. PD-1 inhibitor immunotherapies have revolutionised cancer treatment and are now commonly used to treat melanoma. However new treatment options are still needed to extend the benefit to patients for whom immunotherapies do not work (treatment-resistant patients). This can be up to 50% of all advanced melanoma patients. MB097 is a once daily, orally administered LBP consisting of a defined consortium of nine strains of commensal bacteria designed to enhance the efficacy of immune checkpoint inhibitors (ICIs).

Microbiotica announced the start of its first clinical trial with MB097, in November 2024 the MELODY-1 study. The study is investigating the safety, tolerability, and initial signals of efficacy of MB097 in advanced (metastatic) melanoma, in combination with KEYTRUDA® (pembrolizumab), MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy, in patients with cutaneous melanoma who have failed to respond to immunotherapies. MSD will supply KEYTRUDA (study identifiers NCT06540391; MSD KEYNOTE-E75; 023-507377-17).

The bacterial strains in MB097 were identified by analysing the microbiome of patients in multiple studies of ICIs in melanoma, including the MELRESIST study carried out with the company’s collaborators at Cambridge University Hospitals, UK. Collectively, the MB097 bacterial consortium provides microbiome signalling that appears to be needed for ICI response.

About Microbiotica

Microbiotica is a private, clinical-stage, biopharma company developing a pipeline of oral precision microbiome medicines called live biotherapeutic products (LBPs) with lead programmes in immuno-oncology and inflammatory bowel disease. The company has a clinic-led, purpose-built, proprietary, microbiome profiling platform to support drug discovery based on clinical data, which enables precision identification of bacteria associated with favourable clinical trial outcomes in specific patient populations. The company has significant expertise in microbiology, bioinformatics, translational biology and LBP manufacturing and development. 

The Company is creating a novel pipeline of programmes in immuno-oncology (MB097 for advanced melanoma), and inflammatory bowel disease (MB310 for ulcerative colitis). It has a major partnership with Cancer Research UK and Cambridge University Hospitals in immuno-oncology. The company has a clinical trial supply agreement with MSD (Merck & Co., Inc., Rahway, NJ, USA) for use of KEYTRUDA in evaluating MB097 in melanoma patients with primary resistance to anti-PD-1 immunotherapy. MB310 was developed in collaboration with the University of Adelaide. Both programmes have data read-outs in 2025.

Spun out of the Wellcome Sanger Institute in 2016, the Company is based in purpose-built facilities at the Chesterford Research Park near Cambridge, UK. Microbiotica has raised more than £62 million equity investment, including a £50 million Series B in 2022, with venture investors including British Patient Capital, Cambridge Innovation Capital, Flerie Invest, IP Group plc, Seventure Partners and Tencent. The company has also received financial support from the US-based Crohn’s and Colitis Foundation.

For more information, please visit www.microbiotica.com, and follow us on LinkedIn.

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