Pembrolizumab Demonstrates Improved Overall Survival as Initial Treatment of Recurrent or Metastatic HNSCC


Although recent trials for Merck's pembrolizumab injection demonstrated promise for recurrent or metastatic head and neck squamous cell carcinoma, testing for patients with metastatic triple-negative breast cancer did not meet the primary endpoint.

Merck's pembrolizumab (Keytruda) injection, an anti-PD-1 therapy, in combination with chemotherapy has been found to reduce the risk of death by 40% in patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) whose tumors expressed PD-L1 with a combined positive score equal to or less than 20. In the Phase 3 KEYNOTE-048 trial, the combination demonstrated significantly longer overall survival when compared to the regimen of cetuximab with carboplatin or cisplatin plus 5-fluorouracil (Extreme), which is the current standard of care.1

The data was announced today at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.1

According to Jonathan Cheng, MD, vice president of clinical research at Merck Laboratories, the study results indicated how pembrolizumab works as a monotherapy and in combination with chemotherapy as a potential first-line treatment options for patients with HNSCC.1

The FDA recently granted priority review for a new supplemental Biologics License Application seeking approval for Merck's pembrolizumab as a monotherapy or in combination with platinum and 5-FU chemotherapy for the first-line treatment of patients with recurrent or metastatic HNSCC. Action on the application may be taken in June 2019.1

Although results of the KEYNOTE-048 trial show promise for pembrolizumab, Merck revealed earlier this month that the Phase 3 KEYNOTE-119 trial evaluating this drug as a monotherapy for the second- or third-line treatment of patients with metastatic triple-negative breast cancer (TNBC) was not found to meet the primary endpoint of superior overall survival (OS) compared to chemotherapy. Other endpoints were not formally tested, since the primary OS was not met.2

“Metastatic triple-negative breast cancer is an aggressive and challenging disease to treat, especially after progression on initial standard-of-care treatment,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories, in a prepared statement.2 “While we are disappointed by the outcome of this monotherapy trial, we are continuing to study pembrolizumab in earlier stages of the disease and in combination with chemotherapy to address the unmet medical need of patients with triple negative breast cancer. We are grateful to the patients and investigators for their participation in this important study.”

KEYNOTE-119 is a Phase 3 randomized trial evaluating pembrolizumab monotherapy compared to single-agent physician’s choice chemotherapy in metastatic TNBC. The study randomized 622 patients to receive either pembrolizumab as monotherapy or physician’s choice of single-agent chemotherapy at a ratio of 1:1.2

The pembrolizumab breast cancer clinical development program encompasses several internal and external collaborative studies, including 3 ongoing registration-enabling studies in TNBC (KEYNOTE-355, KEYNOTE-242, and KEYNOTE-522).2


  • Merck’s KEYTRUDA® (pembrolizumab) Demonstrates Improved Overall Survival as First-Line Treatment of Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma at Final Analysis of Pivotal Phase 3 KEYNOTE-048 Trial [press release]. Published May 31, 2019. Accessed May 31, 2019.
  • Merck Provides Update on Phase 3 KEYNOTE-119 Study of KEYTRUDA® (pembrolizumab) Monotherapy in Previously-Treated Patients with Metastatic Triple-Negative Breast Cancer [news release]. Kenilworth, NJ; May 21, 2019: Merck. Accessed May 21, 2019.

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