Microbiotica, a clinical-stage biopharma company developing precision microbiome medicines, has completed patient recruitment for its Phase 1b MELODY-1 trial evaluating MB097 in combination with pembrolizumab for treatment-resistant advanced melanoma. The international study enrolled 41 patients across clinical centers in the UK, France, Italy, and Spain, with initial results expected in the first half of 2026.
Novel Microbiome Approach to Immunotherapy Resistance
The MELODY-1 study represents a first-in-human, randomized open-label clinical trial designed to evaluate the safety and tolerability of MB097 in patients with melanoma who demonstrate primary resistance to anti-PD-1 therapy. All participants receive MB097 and pembrolizumab for up to six months, with half also receiving vancomycin before starting co-therapy to determine whether it helps the bacterial strains in MB097 embed and grow in the gut more efficiently.
MB097 is a once-daily, orally administered live biotherapeutic product consisting of a defined consortium of nine strains of commensal bacteria specifically designed to enhance the efficacy of immune checkpoint inhibitors. The bacterial strains were identified through analysis of the microbiome of patients in multiple studies of immune checkpoint inhibitors in melanoma, including the MELRESIST study conducted with collaborators at Cambridge University Hospitals.
Addressing Critical Treatment Gap
The trial targets a significant unmet medical need in melanoma treatment. While PD-1 inhibitor immunotherapies have revolutionized cancer treatment and are commonly used for melanoma, up to 50% of all advanced melanoma patients do not respond to these treatments. There is growing evidence demonstrating that the composition of the gut microbiome can significantly influence a patient's ability to respond to immunotherapy.
Preclinical studies demonstrate that MB097 activates core pathways of the immune system, including cytotoxic T lymphocytes and natural killer cells, enabling them to kill tumor cells. Research into the mechanism of action of the nine bacterial strains indicates that in addition to this immune-activating effect, the bacteria in MB097 produce metabolites that act directly at the site of the tumor.
Clinical Trial Design and Partnership
The study is conducted in partnership with MSD (Merck & Co., Inc.), which supplies KEYTRUDA (pembrolizumab) for the trial. Participants who benefit from treatment at the end of the initial six-month period may continue to receive pembrolizumab for up to an additional 18 months, for approximately 24 months total treatment duration.
Dr. Robert Tansley, Microbiotica's Chief Medical Officer, commented on the milestone: "In cancer patients, the bacteria in MB097 appear to be associated with better response rates to immune checkpoint inhibitor therapies, such as anti-PD-1 drugs. MB097, with its precisely selected microbes based on data from responsive patients, in combination with ICIs, could therefore activate a therapeutic benefit for non-responding patients with advanced melanoma."
Safety Profile Expectations
The company anticipates a favorable safety profile for MB097, as the bacterial strains are found in healthy subjects as well as in patients who responded to immune checkpoint inhibitors. This natural occurrence of the bacterial consortium in healthy individuals suggests the therapy may be well-tolerated.
Microbiotica, spun out of the Wellcome Sanger Institute in 2016, has raised more than £62 million in equity investment, including a £50 million Series B in 2022. The company operates from purpose-built facilities at Chesterford Research Park near Cambridge, UK, and maintains partnerships with Cancer Research UK and Cambridge University Hospitals in immuno-oncology research.
