Merck's Keytruda prolongs life in big lung cancer study

Advanced lung cancer patients who took Merck & Co Inc's Keytruda immuno-oncology medicine in a large trial and were previously untreated went longer without their disease worsening and showed a survival advantage over those given standard chemotherapy, the drugmaker said on Thursday.

An independent data monitoring board recommended that the late-stage trial be stopped due to the favorable results, Merck said, thereby allowing patients who were taking chemotherapy to switch over to the company's treatment.

Keytruda, which takes the brakes off the immune system by blocking a protein called PD-1, is already approved for patients who have undergone previous chemotherapy for advanced non-small lung cancer.

Patients enrolled in the trial had tumors with high levels of PD-L1, a related protein whose presence may help identify which patients are most likely to respond to Keytruda and similar drugs called checkpoint inhibitors.

Merck hopes the new data will allow its injectable drug, which has a list price of about $150,000 a year, to be used earlier as a treatment for the most common form of lung cancer.

Bristol-Myers Squibb Co's approved rival Opdivo is also being tested as a so-called first line treatment for NSCLC, with data expected later this year.

Opdivo's studies have enrolled patients regardless of their PD-L1 levels, helping assure its wider use and greater sales than Keytruda.

John Boris, an analyst with Suntrust Robinson Humphrey, on Thursday forecast that Keytruda will generate annual sales of $7 billion by 2021. But he predicted Keytruda will have only 25 to 30 percent of the first-line NSCLC market, while Opdivo commands a 65 to 70 percent market share.

Shares of Merck rose 2.1 percent in afternoon trading on the New York Stock Exchange, amid slight gains for the ARCA Pharmaceutical Index of large drugmakers.

(Reporting by Ransdell Pierson; Editing by Lisa Von Ahn and Marguerita Choy)