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Breast Cancer · Medical · Neoadjuvant/Adjuvant Immunotherapy

NSABP B-59/GeparDouze

In patients with high-risk, stage II–III triple-negative breast cancer, does adding atezolizumab to neoadjuvant chemotherapy and continuing it after surgery improve pathological complete response and event-free survival compared with chemotherapy alone?

Tumour site
Breast Cancer
Discipline
Medical
Clinical setting
Neoadjuvant/Adjuvant Immunotherapy
Evidence type
Comparative clinical evidence

Absolute Effect

The randomized phase 3 trial enrolled 1,550 patients and compared atezolizumab with placebo added to sequential taxane-carboplatin-anthracycline-based neoadjuvant chemotherapy. Four-year event-free survival was 85.2% versus 81.9%, an absolute difference of 3.3 percentage points; HR 0.80, P=.083. The primary EFS endpoint was therefore not statistically significant.

NNT / NNH: Calculated only when a defensible fixed-time absolute event difference is available. Hazard ratios alone are not converted into NNT.

Clinical interpretation

NSABP B-59 did not meet its primary EFS endpoint for adding atezolizumab to chemotherapy in early TNBC; the positive pembrolizumab evidence from KEYNOTE-522 is a separate regimen and trial.

Limitations

Do not infer a class effect from one checkpoint inhibitor trial; treatment choice should follow the evidence for the exact regimen, stage and eligibility criteria.

Primary / authoritative source

Primary evidence source

Current-practice context · reviewed 14 October 2026

NSABP B-59/GeparDouze did not meet its primary event-free-survival endpoint for adding atezolizumab to neoadjuvant/adjuvant chemotherapy in early triple-negative breast cancer. It should not replace the evidence-supported pembrolizumab-plus-chemotherapy strategy for eligible stage II–III TNBC; distinguish the negative atezolizumab trial from KEYNOTE-522 and consider current biomarker, stage and regulatory criteria.

NSABP B-59 / GeparDouze primary/registry source ↗ · Current guideline guidance ↗