Add-on pembrolizumab prevails in early triple-negative breast cancer

  • Schmid P & al.
  • N Engl J Med
  • 27 Feb 2020

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • Add-on pembrolizumab to chemotherapy bests placebo for pathological complete response (pCR) in patients with early triple-negative breast cancer (TNBC) enrolled in the KEYNOTE-522 phase 3 trial.

Why this matters

  • This is the first phase 3 trial of an immune checkpoint inhibitor in early breast cancer.
  • Findings are likely to lead to regulatory approvals.

Study design

  • Previously untreated patients with stage II or III TNBC were randomly assigned to:
    • 4 cycles of 200 mg pembrolizumab every 3 weeks plus paclitaxel and carboplatin; or
    • 4 cycles of placebo plus paclitaxel and carboplatin.
  • Both groups then received 4 cycles of pembrolizumab or placebo and anthracycline-based chemo.
  • After definitive surgery, patients received pembrolizumab or placebo every 3 weeks for up to 9 cycles.
  • Funding: Merck Sharp & Dohme.

Key results

  • The pembrolizumab-chemo group was more likely to achieve pCR:
    • 64.8% vs 51.2% in the placebo-chemo group;
    • Difference: 13.6% (P<.001>
  • Fewer pembrolizumab-chemo patients had disease progression after a median of 15.5 months:
    • 7.4% vs 11.8%;
    • HR, 0.63 (95% CI, 0.43-0.93).
  • Pembrolizumab-chemo patients had a higher rate of grade ≥3 treatment-related adverse events:
    • 76.8% vs 72.2%;
    • Death: 0.4% vs 0.3%.

Limitations

  • Short duration of follow-up.
  • PFS and OS not yet available.