Merck (MSD ) has reported that its antibody Keytruda (pembrolizumab) met the primary endpoint of overall survival (OS) in the Phase III KEYNOTE-394 clinical trial in Asian patients with advanced hepatocellular carcinoma (HCC ), the most common form of primary liver cancer.

A humanised monoclonal antibody, Keytruda hinders the interaction between programmed death receptor-1 (PD-1) and its ligands, PD-L1 and PD-L2, to trigger T lymphocytes that could impact both tumour cells and healthy cells.

The anti-PD-1 treatment boosts the immune system’s ability to find and fight tumour cells.

The randomised, double-blind Phase III trial assessed Keytruda versus placebo in 453 HCC patients who were already treated with sorafenib or oxaliplatin chemotherapy.

Progression-free survival (PFS), objective response rate (ORR ), duration of response and disease control rate were included as the secondary goals of the trial.

The subjects were randomised to receive either an intravenous dose of Keytruda every three weeks for up to 35 cycles or a placebo, along with best supportive care in both arms.

According to the trial findings, Keytruda plus best supportive care offered a statistically significant increase in OS versus placebo.

Furthermore, the trial met the key secondary goals of PFS and ORR with statistically significant improvements in the Keytruda arm against the placebo arm.

No new safety signals were reported in the trial, Merck noted.

Merck Research Laboratories clinical research vice-president Dr Scot Ebbinghaus said: “Frequently diagnosed at an advanced stage, hepatocellular carcinoma has one of the highest mortality rates of solid cancers.

“Despite recent progress, there remains an unmet need for anti-PD-1 monotherapy after sorafenib, where Keytruda is an established treatment option for patients.

“It is very encouraging that Keytruda significantly improved overall survival in this study, and we look forward to engaging with regulatory authorities as quickly as possible.”

Last month, Merck reported that Keytruda met the primary goal of recurrence-free survival as adjuvant therapy in the Phase III KEYNOTE-716 trial for surgically resected high-risk stage II melanoma patients.