The same regulatory decision that backed Tecentriq MRD selection also highlighted the FDA’s first authorization of a blood-based MRD assay as a companion diagnostic. Signatera was authorized to identify ctDNA-positive post-cystectomy patients likely to benefit from treatment with Tecentriq or Tecentriq Hybreza. Under the FDA’s decision, a negative MRD result corresponded to a high 2-year survival rate without adjuvant therapy, reinforcing the clinical value of molecular stratification after surgery. Beyond bladder cancer, the approval is likely to influence how sponsors design future trials that incorporate ctDNA MRD as an efficacy-enrichment strategy and as a platform for expanding precision oncology. For market participants, it signals that regulators are willing to treat ctDNA MRD not just as a biomarker but as a decision driver with therapeutic consequences.