KEYNOTE-522
The trial that added immunotherapy to pre-surgery chemotherapy for triple-negative breast cancer and, uniquely, improved survival.
1,174 patients. pCR 64.8% vs 51.2%; event-free survival at 5 years 81.2% vs 72.2%; 7-year EFS 78.3% vs 69.8% and OS 85.1% vs 77.2% (ASCO 2026 update). Defines the standard of care for stage II-III TNBC. Open questions: whether adjuvant pembrolizumab is needed after pCR (OptimICE-pCR) and how to escalate for residual disease.
- 64.8 vs 51.2 out of 100 had no cancer left at surgery with Pembrolizumab + chemotherapy compared with Placebo + chemotherapy; 13.6 more per 100.
- Roughly one extra person helped for every 7 treated. That is a rough figure taken from the two percentages, not a guarantee for any one person.
- The p-value (0.00055) says a difference this large would rarely happen by chance; it does not say how large or how useful the difference is.
- This is a surrogate endpoint: it measures the cancer being controlled or absent on scans and tests, which often, but not always, translates into living longer.
- 81.2 vs 72.2 out of 100 free of a major event at 5 years with Pembrolizumab + chemotherapy compared with Placebo + chemotherapy; 9 more per 100.
- Roughly one extra person helped for every 11 treated. That is a rough figure taken from the two percentages, not a guarantee for any one person.
- Put another way, the treated group had about 35 percent lower chance of the event at any given time (hazard ratio 0.65, likely range 0.51 to 0.83).
- This is a surrogate endpoint: it measures the cancer being controlled or absent on scans and tests, which often, but not always, translates into living longer.
- 86.6 vs 81.7 out of 100 alive at 5 years with Pembrolizumab + chemotherapy compared with Placebo + chemotherapy; 4.9 more per 100.
- Roughly one extra person helped for every 20 treated. That is a rough figure taken from the two percentages, not a guarantee for any one person.
- Put another way, the treated group had about 34 percent lower chance of the event at any given time (hazard ratio 0.66, likely range 0.5 to 0.87).
- Overall survival counts deaths from any cause, so it is the most direct measure of whether a treatment helps people live longer.
- 78.3 vs 69.8 out of 100 free of a major event at 7 years with Pembrolizumab + chemotherapy compared with Placebo + chemotherapy; 8.5 more per 100.
- Roughly one extra person helped for every 12 treated. That is a rough figure taken from the two percentages, not a guarantee for any one person.
- This is a surrogate endpoint: it measures the cancer being controlled or absent on scans and tests, which often, but not always, translates into living longer.
- 85.1 vs 77.2 out of 100 alive at 7 years with Pembrolizumab + chemotherapy compared with Placebo + chemotherapy; 7.9 more per 100.
- Roughly one extra person helped for every 13 treated. That is a rough figure taken from the two percentages, not a guarantee for any one person.
- Overall survival counts deaths from any cause, so it is the most direct measure of whether a treatment helps people live longer.
- These results apply to the people the trial enrolled: Early-stage (II-III) TNBC: pembrolizumab + chemotherapy before surgery, pembrolizumab after. People in a different situation may not see the same effect.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
1,174 participants enrolled.
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Pathologic complete response (ypT0/Tis ypN0)primary | Pembrolizumab + chemotherapy | 401 | 64.8% | — | 0.00055 | link |
| Placebo + chemotherapy | 201 | 51.2% | ||||
| Event-free survival at 5 yearsprimary | Pembrolizumab + chemotherapy | 784 | 81.2% | 0.65 (0.51–0.83) | — | link |
| Placebo + chemotherapy | 390 | 72.2% | ||||
| Overall survival at 5 years | Pembrolizumab + chemotherapy | — | 86.6% | 0.66 (0.5–0.87) | 0.002 | link |
| Placebo + chemotherapy | — | 81.7% | ||||
| Event-free survival at 7 years | Pembrolizumab + chemotherapy | — | 78.3% | — | — | link |
| Placebo + chemotherapy | — | 69.8% | ||||
| Overall survival at 7 years | Pembrolizumab + chemotherapy | — | 85.1% | — | — | link |
| Placebo + chemotherapy | — | 77.2% |
Pages like this
not linked directly; found by shared links- TermResidual cancer burden (RCB)
Shares ASCENT-05 / OptimICE-RD (AFT-65, GBG 119, NSABP B-63), TROPION-Breast03, ADC for residual disease after KEYNOTE-522, Pre-surgery platform trials that test combinations on pathological response in months.
- TrialSCARLET (SWOG S2212)
Shares Neoadjuvant ADC + IO replacing anthracycline chemotherapy in TNBC, TNBC roadmap: from 'nothing to target' to ADC + immunotherapy first line, Carboplatin, Pembrolizumab.
- Key paperCheckMate 816: three cycles of nivolumab plus chemotherapy before lung cancer surgery
Shares Event-free / disease-free survival (EFS, DFS, iDFS, RFS), Pathologic complete response (pCR), Paclitaxel / nab-paclitaxel, Carboplatin.
- TrialOptimICE-pCR (A012103)
Shares TNBC roadmap: from 'nothing to target' to ADC + immunotherapy first line, Pathologic complete response (pCR), Pembrolizumab, Triple-negative breast cancer (TNBC).
- TrialASCENT-04 / KEYNOTE-D19
Shares TNBC roadmap: from 'nothing to target' to ADC + immunotherapy first line, Immunotherapy roadmap: Coley's toxins → checkpoint inhibitors → engineered immunity, Pembrolizumab, Triple-negative breast cancer (TNBC).
- TermMajor pathological response (MPR)
Shares Pre-surgery platform trials that test combinations on pathological response in months, Pathologic complete response (pCR), Neoadjuvant / adjuvant / perioperative.
- TrialMATTERHORN
Shares Event-free / disease-free survival (EFS, DFS, iDFS, RFS), Pathologic complete response (pCR), Neoadjuvant / adjuvant / perioperative.
- Key paperNIAGARA: durvalumab before and after cystectomy for muscle-invasive bladder cancer
Shares Event-free / disease-free survival (EFS, DFS, iDFS, RFS), Pathologic complete response (pCR), Neoadjuvant / adjuvant / perioperative, Immune checkpoint inhibitors.