Natera's Signatera assay has demonstrated the ability to accurately predict which patients with muscle-invasive bladder cancer (MIBC) will benefit from adjuvant immunotherapy with Tecentriq (atezolizumab) following surgery, according to top-line results from the Phase III IMvigor011 study.
The trial (NCT04660344) revealed that patients who tested positive using the in vitro companion diagnostic experienced significant improvements in both disease-free survival (DFS) and overall survival (OS) when treated with Roche's Tecentriq post-surgery. Conversely, a preliminary analysis found that patients who remained Signatera-negative after operation achieved positive outcomes without adjuvant treatment, with 88% remaining disease-free 18 months after surgery.
First Personalized ctDNA-Guided Approach in Bladder Cancer
The IMvigor011 study marks the first Phase III trial in this indication to employ a personalized treatment approach guided by the presence of circulating tumor DNA (ctDNA), a key biomarker of molecular residual disease (MRD). MRD is often associated with an increased risk of cancer relapse.
According to Professor Thomas Powles, the study's principal investigator, the IMvigor011 trial results could "open the door for a new treatment paradigm" in MIBC. The approach enables physicians to more accurately determine whether adjuvant treatment is necessary by monitoring cancer presence at the molecular level.
This represents a significant advancement over previous standard of care disease-monitoring techniques such as imaging and bladder endoscopy, which can miss early-stage recurrence events due to their inability to detect MRD in patients.
Clinical Impact and Regulatory Pathway
Following the positive trial outcome, Natera is finalizing its premarket approval application to the US Food and Drug Administration (FDA) for Signatera's use as a companion diagnostic. If approved, the assay could prevent patients with no detectable MRD from experiencing potentially severe immune-related side effects commonly associated with PD-L1 blockers such as Tecentriq, while allowing physicians to prescribe treatment during early stages of relapse.
Regulatory History and Challenges
The positive results come as welcome news for Natera, given previous regulatory setbacks. In 2022, the UK's National Institute for Health and Care Excellence (NICE) declined to approve Signatera for use in the National Health Service (NHS) as a routine MRD test for solid tumors due to insufficient clinical evidence to support its cost-benefit ratio.
The development also follows Natera's involvement in a significant legal dispute, where Guardant Health was awarded $292.5 million—including $175.5 million in punitive damages—after Natera falsely advertised the benefits of Signatera over Guardant's MRD assay, Guardant Reveal.
