The U.S. Food and Drug Administration approved Natera Inc.'s (NASDAQ: NTRA) Signatera CDx as a companion diagnostic for use with adjuvant atezolizumab immunotherapy in muscle-invasive bladder cancer, the company announced.

The approval marks the first FDA-approved companion diagnostic in the field of blood-based molecular residual disease testing. Signatera CDx identifies patients with muscle-invasive bladder cancer who are ctDNA MRD-positive and may benefit from treatment with adjuvant atezolizumab.

The approval follows results from the Phase III IMvigor011 trial, sponsored by Genentech, which were published in The New England Journal of Medicine in October 2025. The trial demonstrated that Signatera MRD-positive patients treated with immunotherapy achieved improvements in disease-free survival and overall survival, while Signatera MRD-negative patients achieved 97% 2-year overall survival with no adjuvant therapy.

"The practice-changing IMvigor011 trial and this approval signal a transformation in cancer care, where MRD is guiding when to treat, whom to treat, and how to treat more precisely," said Professor Thomas Powles, lead principal investigator of IMvigor011 and Chair of Barts Cancer Centre at St. Bartholomew's Hospital.

Approximately 30,000 new diagnoses of muscle-invasive bladder cancer occur annually in the U.S. and 150,000 globally, according to the company. Radical cystectomy is associated with long-term disease control in approximately half of patients with muscle-invasive bladder cancer.

Natera stated that Signatera is supported by more than 185 peer-reviewed publications and has Medicare coverage across multiple cancer types.