Merck’s Keytruda improves overall survival in phase 3 esophageal cancer trial

The phase 3 Keynote-181 study assessing Keytruda as monotherapy in the second-line treatment of advanced or metastatic esophageal or esophagogastric junction carcinoma has achieved a primary endpoint of OS in patients whose tumors expressed PD-L1.

Keytruda is an anti-PD-1 therapy, which works by enhancing the ability of the body’s immune system to help detect and inhibit tumor cells.

It is a humanized monoclonal antibody that prohibits the interaction between PD-1 and its ligands, PD-L1 and PD-L2, enabling to activate T lymphocytes that may affect both tumor cells and healthy cells.

In the phase 3 Keynote-181 study, the patients treated with Keytruda showed a statistically significant improvement in OS compared against patients treated with chemotherapy.

The primary endpoint of OS was also assessed in patients with squamous cell histology, in addition to the entire intention-to-treat (ITT) study population.

Keynote-181 is a randomized, open-label and phase 3 study designed to assess Keytruda monotherapy compared to chemotherapy in patients with advanced or metastatic adenocarcinoma or squamous cell carcinoma of the esophagus or Siewert type I adenocarcinoma of the esophagogastric junction that has progressed after first-line standard therapy.

According to the company, the primary endpoint was OS and secondary endpoints were PFS, ORR and safety/tolerability.

The company recruited over 600 patients in the study and has randomized 1:1 to secure either Keytruda or investigator’s choice of chemotherapy regimens such as docetaxel, paclitaxel and irinotecan.

Merck Research Laboratories global clinical development head, chief medical officer and senior vice president 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 tumors express PD-L1 with a CPS of 10 or greater.

“This marks the sixth tumor 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.”