Clinical Validation of Ataraxis™ Breast Published in Nature Communications

Nature Communications just published a major clinical validation study of Ataraxis™ Breast’s performance. The study included 8,161 patients across 15 cohorts and brought together over 50 academic collaborators. 

Ataraxis™ Breast outperformed the legacy 21-gene assay in a direct head-to-head comparison (n=858), achieving a superior C-index of 0.67 vs. 0.61 and provided independent prognostic value in multivariate analysis (HR: 2.95, p<0.001). The results held across all major breast cancer molecular and histological subtypes, nodal statuses, patient ages, races, and treatment scenarios.‍

Clinical utility highlights:

Ataraxis Breast is prognostic for both early and late recurrence in HR+HER2- patients. Ataraxis Breast high-risk patients had significantly worse outcomes than low-risk patients across treatment settings: in patients who received endocrine therapy alone (C-index: 0.68, HR: 5.01, p=0.03) or chemoendocrine therapy (C-index: 0.70, HR: 4.10, p=0.007). Prognostic value extended to late recurrence (years 5-10) as well (C-index: 0.79, HR: 8.45, p<0.001).‍

Prognostication in underserved populations. Ataraxis Breast was validated in two subtypes with no NCCN-recommended prognostic tools: TNBC (C-index: 0.71, HR: 3.81, p=0.02) and HER2+ (C-index: 0.67, HR: 2.22, p=0.05). Also validated across histological subtypes including lobular breast cancer, and demonstrated consistent performance across patient races and ages.

Full Publication: https://www.nature.com/articles/s41467-026-73088-y