Fecal microbiota transplantation plus pembrolizumab and axitinib in metastatic renal cell carcinoma: the randomized phase 2 TACITO trial

Renal cell carcinoma (RCC) is a common malignancy with limited durable responses to first-line immune checkpoint inhibitor (ICI)-based therapies. Emerging evidence implicates the gut microbiome in modulating ICI efficacy. In the investigator-initiated, randomized, double-blind placebo-controlled phase 2a TACITO trial, we evaluated whether fecal microbiota transplantation (FMT) from complete ICI responders enhances clinical outcomes in treatment-naive patients with metastatic RCC (mRCC) receiving pembrolizumab + axitinib. The primary endpoint was the rate of patients free from disease progression at 12 months after randomization (12-month progression-free survival (PFS)). Secondary endpoints were median PFS and…