
Merck has reported positive data from the Phase III KEYNOTE-181 trial after it met one of its primary endpoints of overall survival (OS).
The study evaluated keytruda in comparison with chemotherapy in patients with advanced / metastatic adenocarcinoma, squamous cell carcinoma of the esophagus, or Siewert type I adenocarcinoma of the esophagogastric junction that has advanced following first-line standard therapy.
Results demonstrated that patients treated with keytruda achieved a statistically significant improvement in OS compared to chemotherapy regardless of their histology.
Merck investigated the primary endpoint of OS in patients with squamous cell histology and in the entire intention-to-treat (ITT) patients.
The company received directionally favourable results, but failed to obtain any statistical significance for OS in these two patient groups.
Key secondary endpoints of progression-free survival (PFS) and objective response rate (ORR) were not formally assessed as the OS was not achieved in the entire ITT study population.

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By GlobalDataIt was also found that the safety profile of keytruda observed in the KEYNOTE-181 trial was similar to those observed in earlier studies.
Merck Research Laboratories senior vice-president and global clinical development head Dr Roy Baynes said: “In this pivotal trial, keytruda resulted in a statistically significant and clinically meaningful improvement over standard chemotherapy in overall survival for patients with advanced esophageal or esophagogastric junction carcinoma whose tumours express PD-L1 with a CPS of ten or greater.
“This marks the sixth tumour type where keytruda has demonstrated a survival benefit, and represents the first time an anti-PD-1 therapy has achieved overall survival for this patient population.”
The KEYNOTE-181 trial enrolled more than 600 patients who were randomised in 1:1 ratio to receive either keytruda or any of the trial’s three chemotherapy regimens.