Merck's Keytruda fails pivotal gastric cancer trial

Merck & Co Inc said on Thursday a key late-stage trial testing its blockbuster drug, Keytruda, failed to meet its main goal of extending lives of patients with a type of gastric cancer.

The trial, which was testing the drug as a second-line treatment, also failed to prevent cancer from progressing in patients whose tumors expressed the PD-LI protein, the company said.

The U.S. regulator earlier this year approved Keytruda as a third-line treatment for gastric cancer patients, who showed no response to two or more prior lines of therapy.

Gastric, or stomach cancer, is a slow-progressing disease and it is estimated that more than 10,000 people will die from it in 2017 in the United States.

Merck said on Thursday that it would continue to test the blockbuster drug in two other late-stage gastric cancer studies.

Keytruda belongs to a class of drugs called PD-1 or PD-L1 inhibitors that block a mechanism tumors use to evade detection from cancer-fighting cells. It is seen as a forerunner of precision medicine, where genetic biomarkers may determine the course of therapy rather than the type of cancer.

The drug, which netted $1.05 billion in sales in the latest quarter, has been previously approved to treat at least five other types of cancer including lung and bladder.