The FDA approved Genentech’s Tecentriq (atezolizumab) and Tecentriq Hybreza as adjuvant treatment for muscle-invasive bladder cancer patients whose circulating tumor DNA (ctDNA) remains positive after cystectomy, using Natera’s Signatera CDx. The approval makes ctDNA molecular residual disease (MRD) guidance a formal companion diagnostic-driven decision point for adjuvant immunotherapy. In the Phase III IMvigor011 trial, 250 patients who were ctDNA-positive by Signatera but had no radiographic evidence of disease were randomized to Tecentriq or placebo. Disease-free survival was 9.9 months versus 4.8 months with placebo, and median overall survival was 32.8 months versus 21.1 months. Genentech and Natera also received simultaneous FDA authorization for Signatera as the blood-based MRD CDx that identifies likely benefit versus patients who can avoid adjuvant therapy. The label positions the approval as the first FDA ctDNA-guided regulatory authorization of a cancer therapy.