The FDA approved Genentech’s Tecentriq (atezolizumab) and Tecentriq Hybreza as adjuvant therapy for muscle-invasive bladder cancer patients who are ctDNA-positive after cystectomy, as determined by Natera’s Signatera CDx MRD assay. The approval marks the first FDA authorization for a ctDNA MRD-guided therapy in this setting. In the Phase III IMvigor011 trial, 250 patients who were Signatera-positive but had no radiographic disease were randomized to Tecentriq versus placebo. Disease-free survival was 9.9 months with Tecentriq compared with 4.8 months on placebo, and median overall survival was 32.8 months versus 21.1 months. Genentech said patients with negative Signatera results after cystectomy may be able to avoid adjuvant treatment, leveraging the MRD assay’s role in patient selection. The FDA also authorized the blood-based Signatera MRD assay as a companion diagnostic for identifying patients most likely to benefit.