- Pembrolizumab with neoadjuvant chemotherapy and then as adjuvant yields good pathologic complete response (pCR) in patients with triple-negative breast cancer (TNBC) with lymph node (LN) involvement.
- Study author said the trend for event-free survival is “favorable” but does not yet meet predefined boundaries for statistical significance.
Why this matters
- These findings from KEYNOTE-522 add to results that showed the benefit of pembrolizumab in metastatic TNBC.
- At a median follow-up of 15.5 months, event rate was 7.4% with pembrolizumab+chemo + pembrolizumab vs 11.8% with placebo+chemo + placebo (HR, 0.63; 95% CI, 0.43-0.93).
- With no LN involvement, pCR rates were:
- 64.9% with pembrolizumab vs 58.6% placebo.
- Difference: 6.3% (95% CI, −5.3% to 18.2%).
- With LN involvement, pCR rates were:
- 64.8% with pembrolizumab vs 44.1% with placebo.
- Difference: 20.6% (95% CI, 8.8%-31.9%).
- pCR was also higher with pembrolizumab in stage III disease.
- Randomized, placebo-controlled trial of 1174 participants with untreated early TNBC (age ≥18 years) from 21 countries.
- All patients underwent chemotherapy with pembrolizumab or placebo (saline), followed by pembrolizumab or placebo as postoperative adjuvant.
- Study is ongoing.
- Primary endpoint: pCR, event-free survival.
- Presentation included analyses of data for LN-involvement group.
- Funding: MSD.
- Event-free survival data are preliminary in the ongoing study.
- Results presented without peer review at a conference.