- Keytruda is limited to patients with tumors that express PD-L1
- Patients' disease also must have progressed on other therapies
Merck & Co. won approval in the U.S. to expand the use of its drug Keytruda to treat a form of advanced lung cancer, though only in patients whose tumors have a biological marker signaling the medicine may work.
The Food and Drug Administration cleared Keytruda for sale to patients who have non-small cell lung cancer, the most common form of the disease, and whose condition has progressed despite other treatments, according to a statement from the agency. Patients’ tumors should also express a protein called PD-L1, the FDA said, that the drug interacts with to help unleash the immune system against cancer cells.
In a study Merck conducted, about 22 percent of lung cancer patients had significant levels of PD-L1, though it’s not yet definitively known how the levels might change over time, or if there’s a firm level of the protein below which drugs targeting the pathway won’t work.
The lung cancer approval comes seven months after Bristol-Myers Squibb Co.’s related therapy Opdivo was approved for patients with a form of the disease called squamous non-small cell lung cancer. About 25 percent to 30 percent of all lung cancers are squamous, with non-small cell lung cancer making up the vast majority of cases, according to the American Cancer Society. Bristol-Myers’ drug doesn’t come with a requirement that patients show significant levels of PD-L1.
Merck shares fell 1.5 percent to $48.63 at 2:07 p.m. in New York. Bristol-Myers rose 3.9 percent to $62.37.
Keytruda was originally approved a year ago for advanced melanoma, becoming the first in a new line of treatments that use patients’ own immune systems to attack tumors. The FDA cleared the drug for both cancers under a program known as accelerated approval, which allows promising therapies on the market while their makers conduct further studies to make sure they extend lives.
About 221,200 new cases of lung cancer are expected to be diagnosed in the U.S. this year, almost triple the number of estimated melanoma cases, according to the American Cancer Society. Lung cancer is also by far the leading cause of cancer death in the U.S. About 85 percent to 90 percent of lung cancers are classified as non-small cell.
Keytruda, which costs about $150,000 a year, is expected to generate $2.14 billion in sales in 2017, according to analysts’ estimates compiled by Bloomberg.
The drug targets the cellular pathway known as PD-1/PD-L1, which affects the immune system’s ability to recognize and kill malignant cells. In a trial, lung cancer patients whose disease tested positive for the PD-L1 were more likely to respond to Keytruda. The results, published in May in the New England Journal of Medicine, found that 19.4 percent of all patients responded to the drug, compared with 45.2 percent whose tumor cells expressed a certain amount of the molecule.
They also lived longer before their disease got worse -- patients with a certain amount of PD-L1 went 6.3 months before their cancer progressed, compared with 3.7 months for all patients.
A test will let doctors examine the tumors for PD-L1 levels before treatment. Dako North America Inc., a subsidiary of Agilent Technologies Inc., won approval Friday as well of a companion diagnostic test that detects PD-L1 expression.