Randomized phase 1 trial of nivolumab-ipilimumab with or without live bacterial supplementation for metastatic renal cell carcinoma

Previous studies have suggested that the gut microbiome influences the response to checkpoint inhibitors in patients with cancer. CBM588 is a bifidogenic live bacterial product. A randomized phase 1 study at City of Hope Comprehensive Cancer Center (Duarte, CA) randomized patients with treatment-naïve metastatic renal cell carcinoma to nivolumab plus ipilimumab with or without CBM588. There was no difference between the two groups for the primary endpoint, stool relative abundance of Bifidobacterium spp. at 12 weeks. However, clinical endpoints were better with CBM588. The authors conclude that CBM588 appears to enhance the clinical outcome in patients with metastatic renal cell carcinoma treated with nivolumab-ipilimumab.