By Peter Loftus
The U.S. Food and Drug Administration approved Merck & Co.'s Keytruda for the treatment of the most common form of lung cancer, the second of a costly new wave of immune-boosting drugs to be cleared for one of the deadliest cancer types.
The FDA cleared Keytruda for use in patients with non-small-cell lung cancer whose tumors contain a certain level of a protein known as PD-L1, and whose disease continued to worsen after the patient received chemotherapy or other drugs. The FDA also approved a companion diagnostic developed by Dako North America Inc. to test for PD-L1, to screen for patients who should receive Merck's Keytruda.
A Merck-funded study found that Keytruda worked better in lung-cancer patients with higher levels of PD-L1 than in patients with lower or undetectable levels. Merck estimates roughly 25% of all non-small-cell lung-cancer patients have PD-L1 levels that would make them eligible for Keytruda treatment, Roger Perlmutter, Merck's research chief, said in an interview Friday.
Merck shares rose 1.6% Friday, after initially declining on the news. Some analysts say the requirement that Keytruda be used in PD-L1-positive patients could provide a competitive advantage to a rival drug from Bristol-Myers Squibb Co., Opdivo, which isn't limited to PD-L1-positive patients.
Keytruda joins Opdivo as a new immunotherapy option for certain patients with non-small-cell lung cancer, which accounts for about 85% to 90% of all lung-cancer cases. The National Cancer Institute estimates 221,200 Americans will be diagnosed with lung cancer this year, and 158,040 will die from it.
Both Keytruda and Opdivo work by blocking a substance on immune cells known as PD-1, disrupting its interaction with PD-L1 on cancer cells. This lifts a natural brake on the immune system and allows it to kill cancer cells. Doctors believe the anti-PD-1 drugs have potential to transform treatment of multiple tumor types, based on clinical trials showing improvements in survival and tumor-shrinkage rates versus some older treatments.
Analysts estimate the class has multi-billion-dollar sales potential--fueled by hefty prices. Keytruda and Opdivo both cost about $12,500 a month per patient, or $150,000 if used for a full year. Both drugs were previously approved to treat melanoma. Merck recorded $192 million in Keytruda sales for the first six months of 2015.
On Thursday, the FDA approved the use of a combination of Opdivo and an older Bristol immunotherapy, Yervoy, for the treatment of melanoma. The two-drug combination would cost about $256,000 for the first full year.
Expanding the use of these high-price immunotherapies to multiple tumor types could pose a new cost burden for insurers and other payers. In May, Leonard Saltz, an oncologist from Memorial Sloan Kettering Cancer Center called prices for new cancer drugs "unsustainable" in a speech at a meeting of cancer doctors.
FDA approval of Keytruda for lung cancer was based partly on a study showing it significantly shrank tumors in about 19% of lung-cancer patients. Among those with a certain level of PD-L1 expression, the response rate was 41%, according to the FDA. The most common side effects of Keytruda include fatigue and breathing problems.
"I think there's going to be more and more interest on the part of oncologists in using PD-L1 expression in making decisions about how best to treat their lung-cancer patients," Merck's Dr. Perlmutter said.
Write to Peter Loftus at email@example.com