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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Monday, April 18, 2022
Peter Schmid, MD, PhD, of Barts Cancer Institute, Queen Mary University of London, United Kingdom, and colleagues reported results regarding event-free survival—a primary endpoint—among patients with triple-negative breast cancer treated with pembrolizumab and chemotherapy. Published in The New England Journal of Medicine, the findings of the phase III KEYNOTE-522 trial concluded that when neoadjuvant pembrolizumab was added to chemotherapy and surgery regimens in these patients, it produced significantly longer event-free survival than chemotherapy alone.
“The addition of pembrolizumab did not compromise exposure to chemotherapy or increase the incidence of common chemotherapy-related toxic effects,” concluded the study authors. “The results of this trial support the use of pembrolizumab plus platinum-, taxane-, and anthracycline-containing neoadjuvant chemotherapy, followed by adjuvant pembrolizumab after surgery, as a treatment regimen for patients with high-risk, early triple-negative breast cancer, regardless of tumor PD-L1 expression status.”
The KEYNOTE-522 trial enrolled 1,174 patients with previously untreated stage II or III triple-negative breast cancer. Participants were randomly assigned to receive neoadjuvant therapy with four cycles of pembrolizumab (n = 784) or placebo (n = 390) plus doxorubicin/cyclophosphamide or epirubicin/cyclophosphamide. After surgical intervention, individuals received adjuvant pembrolizumab or placebo every 3 weeks for up to nine cycles.
The median follow-up of this fourth interim analysis was 39.1 months. Approximately 15.7% of patients given pembrolizumab and 23.8% of patients given placebo had an event or died. At 36 months, the estimated event-free survival was significantly higher among patients in the pembrolizumab/chemotherapy (84.5%) group than in the placebo/chemotherapy (76.8%) group (hazard ratio [HR] = 0.63; P < .001).
The most common adverse event that determined event-free survival was distant recurrence, affecting 60 participants in the pembrolizumab/chemotherapy group and 51 in the placebo/chemotherapy group. Notably, adverse events were reported principally during the neoadjuvant phase of treatment and appeared to be consistent with the established safety profiles of both pembrolizumab and chemotherapy alone.
Disclosure: For full disclosures of the study authors, visit nejm.org.
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