Microbiotica has presented new phase 1b clinical data for MB097, its oral precision microbiome therapeutic for advanced melanoma, at the ESMO Congress 2026 in Madrid. The MELODY‑1 trial met all primary and secondary endpoints and showed encouraging efficacy signals in a population refractory to anti‑PD‑1 therapy.
Professor Paolo Ascierto said: “The advanced melanoma patients enrolled in MELODY‑1 had recently received anti-PD-1 therapy but continued to experience disease progression. Many had received multiple prior lines of treatment, including combination immune checkpoint inhibitor regimens, without achieving a meaningful clinical benefit.
“This represents a particularly challenging patient population with limited therapeutic options. It is therefore encouraging to observe clinically meaningful responses, including deep tumour regressions, suggesting that modulation of the gut microbiome with MB097 may help restore sensitivity to pembrolizumab in patients previously refractory to anti-PD-1 therapy.
He added: “These findings provide an important early clinical proof-of-concept for microbiome-based strategies aimed at enhancing the effectiveness of cancer immunotherapy and warrant further investigation in larger clinical studies.”
The poster presentation highlighted that MB097 was safe and well tolerated in combination with pembrolizumab, with no serious adverse effects related to MB097. The nine‑strain consortium showed rapid and persistent engraftment, particularly in patients receiving vancomycin preconditioning. Three of 21 patients in the vancomycin arm achieved an objective response, including one complete response, compared with two of 20 in the non‑vancomycin arm.
The international study enrolled 41 patients whose melanoma had failed to respond at any time to anti‑PD‑1 therapy. Participants were randomised to receive either five days of vancomycin followed by washout or no preconditioning before starting MB097 plus pembrolizumab for 24 weeks. All patients completed treatment and safety follow‑up.
Robert Tansley, Chief Medical Officer of Microbiotica, said: “Growing evidence highlights the role of the gut microbiome in patients’ responses to immune checkpoint inhibitors, particularly anti-PD-1 therapies.
“The data presented at ESMO from our phase 1b MELODY-1 study demonstrates that MB097 was safe and well tolerated in combination with KEYTRUDA, with robust, persistent engraftment of the bacterial consortium and encouraging clinical responses in this challenging patient population.”
