# GeparDouze / NSABP B-59

Source: https://onco.cc/trials/gepardouze/  
OnCo record `gepardouze` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

GeparDouze, the largest neoadjuvant immunotherapy trial in triple-negative breast cancer, found that adding atezolizumab to chemotherapy before and after surgery did not significantly reduce relapses (a 3.3-point gain at four years that missed statistical significance), unlike pembrolizumab in KEYNOTE-522.

## Summary

NSABP B-59/GeparDouze (NCT03281954) randomised 1,550 patients (773 atezolizumab, 777 placebo) with stage II to III triple-negative breast cancer to sequential taxane, carboplatin and anthracycline neoadjuvant chemotherapy with atezolizumab or placebo, continued after surgery. The primary endpoint, event-free survival, was not significantly improved (hazard ratio 0.80, 95 percent confidence interval 0.62 to 1.03, stratified log-rank p 0.083; four-year rates differed by 3.3 points); the overall survival hazard ratio was 0.86 (0.62 to 1.19) with a 0.7-point four-year difference. A prespecified subgroup analysis suggested benefit in patients with clinical nodal involvement (interaction p 0.039), and an exploratory mRNA analysis pointed to basal-like immune-activated tumours. Grade 3 or worse treatment-emergent adverse events were 75.3 versus 73.4 percent and immune-related adverse events 27.6 versus 11.4 percent; 25.5 percent discontinued atezolizumab in the neoadjuvant phase against 18.8 percent for placebo. Published in Nature Medicine in 2026, the trial leaves pembrolizumab as the only checkpoint inhibitor with an early-stage triple-negative licence.

## Fields

- Kind: Trial
- Status: negative
- Last checked: 2026-09-24
- Also known as: NSABP B-59; GBG 96; GeparDouze
- Registry id: NCT03281954
- Phase: 3
- Setting: Stage II to III triple-negative breast cancer: neoadjuvant taxane, carboplatin and anthracycline chemotherapy with atezolizumab or placebo, then adjuvant atezolizumab or placebo, United States, Canada and Germany
- Sponsor: NSABP Foundation / German Breast Group, with Genentech and Roche
- Enrolled: 1550
- Result: EFS HR 0.80 (0.62 to 1.03), p 0.083, not significant; OS HR 0.86 (0.62 to 1.19).
- Outcomes: Event-free survival (four-year difference 3.3 points): Atezolizumab + chemotherapy vs Placebo + chemotherapy, HR 0.8; Overall survival (four-year difference 0.7 points): Atezolizumab + chemotherapy vs Placebo + chemotherapy, HR 0.86
- Replication: Consistent with NeoTRIP (no pCR gain) and ALEXANDRA/IMpassion030 (adjuvant, futile); discordant with KEYNOTE-522 (pembrolizumab, EFS HR 0.63).

## Sources

- ClinicalTrials.gov NCT03281954: https://clinicaltrials.gov/study/NCT03281954
- Geyer, Loibl et al., Nature Medicine 2026: atezolizumab in early triple-negative breast cancer, NSABP B-59/GeparDouze: https://doi.org/10.1038/s41591-026-04565-6

## Connected records

- cancers: [Early triple-negative breast cancer](https://onco.cc/cancers/tnbc-early/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- technologies: [Cytotoxic chemotherapy](https://onco.cc/technologies/cytotoxic-chemotherapy/), [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [Platinum agents](https://onco.cc/technologies/platinum/)
- drugs: [Atezolizumab](https://onco.cc/drugs/atezolizumab/), [Carboplatin](https://onco.cc/drugs/carboplatin/), [Cyclophosphamide](https://onco.cc/drugs/cyclophosphamide/), [Doxorubicin](https://onco.cc/drugs/doxorubicin/), [Epirubicin](https://onco.cc/drugs/epirubicin/), [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/)
- companies: [German Breast Group (GBG)](https://onco.cc/companies/gbg/), [Roche / Genentech](https://onco.cc/companies/roche-genentech/)
- terms: [Event-free / disease-free survival (EFS, DFS, iDFS, RFS)](https://onco.cc/terms/efs/), [Immune-related adverse events (irAEs)](https://onco.cc/terms/irae/), [Tumour-infiltrating lymphocytes (TILs)](https://onco.cc/terms/tils/)
- trials: [ALEXANDRA / IMpassion030](https://onco.cc/trials/impassion030/), [IMpassion031](https://onco.cc/trials/impassion031/), [KEYNOTE-522](https://onco.cc/trials/keynote-522/), [NeoTRIP (NeoTRIPaPDL1)](https://onco.cc/trials/neotrip/)

---
JSON: https://onco.cc/api/v1/entities/gepardouze.json