Merck’s Keytruda could offer ‘paradigm shift’ in lung cancer treatment 

Impressive data from a large clinical trial of Merck & Co.’s immunotherapy Keytruda herald a new approach to treating certain kinds of lung cancer. The results, which are being called a paradigm shift, were reported this week at the American Association for Cancer Research (AACR) meeting in Chicago.

The Phase III study explored whether adding Keytruda to chemotherapy, the current standard of care, could extend the lives of people with advanced lung cancer. The definitive answer was yes. In the study of more than 600 patients, people given the combination were half as likely to die from their disease as those given chemotherapy alone.

Combining Keytruda and chemotherapy “really may represent a new standard of care for this group,” Leena Gandhi, director of thoracic medical oncology at New York University’s Perlmutter Cancer Center, and a leader of the study, told reporters at the meeting. Notably, Keytruda benefited everyone in the trial—regardless of whether their tumors expressed PD-L1, a biomarker often used to predict the response to immunotherapies like Keytruda.

Keytruda is a checkpoint inhibitor, an antibody that releases the brakes on immune cells, allowing them to see and kill cancer cells. At AACR, an early look at a study of another checkpoint inhibitor, Bristol-Myers Squibb’s Opdivo, in lung cancer was less of a slam dunk. That Phase III trial, which is ongoing, has yet to so neatly show that combining Opdivo and a second checkpoint inhibitor, Yervoy, helps lung cancer patients live longer than when given chemotherapy.

Opdivo’s failure to produce as clear of an advantage over chemotherapy as Keytruda left some puzzled. In a note to investors, Evercore ISI stock analyst Umer Raffat questioned whether the differences in lung cancer efficacy are due to the design of the trials or subtle differences in drugs that work against the same target.

A win for Keytruda in lung cancer would give Merck a significant leg up in the competitive immuno-oncology market. Both drugs were initially approved to treat melanoma, but have since expanded into other cancer types. Last year, Opdivo sales totaled $4.9 billion, while Keytruda brought in $3.8 billion.

But David Jablons, director of UCSF Helen Diller Comprehensive Cancer Center’s thoracic oncology laboratory, who did not participate in the trials, suggests not reading too much into the differences in the Merck and BMS data. Rather, he says the take-home message should be that immunotherapy can be oncologists’ first line of defense against advanced lung cancer.

The results are “a paradigm shift,” Jablons says. “These studies completely change the way we approach advanced-stage lung cancer.”