In early 2015, Merck & Co.'s drug Keytruda has been approved to treat melanoma, a type of skin cancer. Keytruda's FDA approval as a lung cancer treatment was announced on Oct. 2, 2015.
Also known as 'pembrolizumab', Keytruda is designed for patients with advanced non-small cell lung cancer (NSCLC). Patients who suffer from the illness have tumors with a specific protein called 'programmed cell death protein 1' or PD-L1. Keytruda contains an antibody which targets another protein called PD-1. When PD-L1 and PD-1 bind together, PD-1 lowers T lymphocytes or T-cells in the immune system. Normal levels of T-cells help the body fight cancer cells. Evidently low levels of T-cells are prominent in HIV/AIDS patients.
By blocking the interaction between proteins PD-L1 and PD-1 in the molecular pathway, Keytruda could help the immune system to fight off cancer cells.
An accompanying diagnostic, the PD-L1 IHC 22C3 pharmDx test, has also been approved by the FDA. This is the first diagnostic test to detect PD-L1 proteins in lung cancer patients.
"The approval of this drug and a test to identify patients most likely to benefit has the potential to transform the way that lung cancer is treated," said Dr. Edward Garon, who led the Keytruda study at the University of California Los Angeles' Jonsson Comprehensive Cancer Center.
Keytruda was initially tested on 550 NSCLC patients and many showed long-term response to the medicine. In 2014, Keytruda was dubbed by as a "breakthrough therapy", which paved the way for a fast-tracked approval.
Dr. Richard Pazdur from the FDA commended that understanding the interaction of the body's immune system with cancer has led to many advancement in medication and therapy. Keytruda's approval will give doctors the facility to detect patients who may benefit from the immune therapy drug, he added.
Lung cancer is the leading killer cancer type in the U.S. The National Cancer Institute has estimated 221,200 new cases of lung cancer will be diagnosed in 2015 along with 158,040 deaths.
Merck & Co., an American pharmaceutical company based in New Jersey, markets the new lung cancer drug. The accompanying PD-L1 IHC 22C3 pharmDx diagnostic test is being marketed by California-based Dako North America Inc., a leading cancer diagnostics company.
