Pembrolizumab added to neoadjuvant and adjuvant chemotherapy improves event-free survival in patients with early triple-negative breast cancer (TNBC).
High-risk early-stage TNBC is associated with early recurrence and high mortality. Neoadjuvant chemotherapy is the preferred treatment approach. Previous results from KEYNOTE-522 (NCT03036488) showed statistically significant and clinically meaningful improvements in pathological complete response (pCR) and event-free survival (EFS) with the addition of pembrolizumab to neoadjuvant platinum-containing chemotherapy followed by adjuvant pembrolizumab in patients with early-stage TNBC.1,2 Based on these results, the EMA and FDA have approved this treatment for high-risk early-stage TNBC.
Dr. Peter Schmid of Barts Cancer Institute, London, presented updated results after a median follow-up of 5 years.3 The phase 3 KEYNOTE-522 trial enrolled 1174 participants with previously untreated TNBC (stages T1c N1-2 or T2-4 N0-2) who were randomized 2:1 to neoadjuvant pembrolizumab with chemotherapy or placebo with chemotherapy. After surgery, patients received adjuvant pembrolizumab or placebo for 6 months or until recurrence or unacceptable toxicity. Dual primary endpoints were pCR and EFS
After 5 years of follow-up, EFS rates were 81.3% (95% CI, 78.4%-83.9%) and 72.3% (95% CI, 67.5%-76.5%) respectively for patients treated with pembrolizumab or placebo (HR, 0.63; 95% CI, 0.49-0.81). For comparison, EFS rates at 3-year follow-up were 84.5% and 76.8%, respectively (HR, 0.63; 95% CI, 0.48-0.82)
“The curves are starting to flatten out,” said Dr. Schmid. The benefit of pembrolizumab was observed within all predefined subgroups, including grouping by PD-L1 expression and nodal status. Overall survival data are not yet mature and were not presented
“The updated results of KEYNOTE-522 provide further support for neoadjuvant pembrolizumab plus platinum-containing chemotherapy followed by adjuvant pembrolizumab in early-stage TNBC patients,” concluded Dr. Schmid.
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