But trials over the last five years have repeatedly shown more uses for immune therapy in lung cancer, and the new research confirms that almost all lung cancer patients will now receive immune therapy, said Patrick Forde, the first author on one of the studies and a lung cancer specialist at Johns Hopkins Medical.
Another study found that an immunotherapy combo - the Bristol-Myers Squibb drugs Opdivo and Yervoy - worked better than chemo for delaying the time until cancer worsened in advanced lung cancer patients whose tumors have many gene flaws, as almost half do.
Keytruda - developed by pharmaceutical giant Merck, which also funded the study - turns off cancer cell's protective functions, letting the immune system recognize and attack the cells.
The findings, published in the the New England Journal of Medicine, were reported on Monday at the American Association for Cancer Research annual meeting in Chicago.
"Non-small cell lung cancer is actually the leading cause of cancer death in the world even though it's not the most common cancer", said Dr. Leena Gandhi, lead investigator of the study and director of the thoracic medical oncology program at Perlmutter Cancer Center at NYU Langone Health.
Hellmann's study, called CheckMate 227, found that advanced tumors that contain a lot of genetic mutations - often from smoking - respond particularly well to a combination of two immune therapy drugs, Yervoy and Opdivo, both from Bristol-Myers Squibb.
All of these immune therapy treatments worked for only about half of patients, but that's far better than chemo has done in the past. Those not given Keytruda were allowed to switch to it if their cancer worsened. More research is needed to know if the combo improves overall survival, as Keytruda did.
For non-squamous non-small cell lung cancer patients, median survival with chemotherapy alone is somewhere around 11 or 12 months, he said. But that is advance in this cancer. "This is really a pivotal study. a new standard of care", said Shaw, who has no ties to the drugmakers.
Dr. Jorge Gomez, a volunteer spokesperson for the American Lung Association and a medical oncologist and director of thoracic oncology at Mount Sinai Hospital in NY, explained that "about 220,000 patients are diagnosed with lung cancer a year in the USA".
Of 679 patients, 299 had a high number of gene flaws in their tumors. At one year, 43% percent of patients on the combination therapy had not seen any progression of their cancer, compared to 13% of those with chemotherapy. By killing some tumor cells, chemotherapy could pop open the bags, release the contents and help immune cells unleashed by the checkpoint drugs to identify their prey.
Another rival, Genentech, recently announced that its checkpoint inhibitor, Tecentriq, improved survival in a study similar to the one testing Keytruda.
Gandhi said chemotherapy alone had only a "modest benefit", and could add only a few months of life, with most patients surviving about a year or less.
But patients in the immunotherapy group had more kidney problems, more immune-related adverse events and were more likely to stop treatment because of side effects. Details are expected in a couple months.