Clinical trial (TACITO) for the evaluation of the efficacy of targeted of fecal microbiota transplantation (FMT) in improving response rates to immune checkpoint inhibitors (ICIs) in subjects with treatment-naïve metastatic renal cell carcinoma.

Clinical trial (TACITO) for the evaluation of the efficacy of targeted fecal microbiota transplantation (FMT) in improving response rates to immune checkpoint inhibitors (ICIs) in subjects with treatment-naïve metastatic renal cell carcinoma. In this investigator-initiated phase 2a placebo-controlled randomized clinical trial, FMT from donors who are responding to ICIs (or a placebo FMT, in the control arm) was combined with first-line therapy with pembrolizumab and axitinib. Patients underwent the first FMT infusion by colonoscopy. Then, patients received frozen fecal capsules (8 capsules t.i.d.) at 3 and 6 months after the first FMT. Stool samples from donors were collected from all donated aliquots, and from patients at baseline, one, four, 12, 24, 36, and 52 weeks after the first treatment, which was followed by shotgun metagenomic sequencing and microbiome characterization for donor strain engraftment estimation.