An interesting story from NBC News. A new drug, called Keytruda, can apparently use the body’s own immune system among some patients to fight both lung cancer and melanoma.

According to the NBC News article:

Garon’s team tested Keytruda in 495 lung cancer patients. The drug targets mutations in genes called PD-1 and PD-L1. These mutations let some tumors escape detection and destruction by immune system cells that normally prevent cancer from spreading in the body. … It worked in about 19 percent of the patients,

Before you think 19 percent is a petty amount — keep in mind lung cancer is the No. 1 cancer killer in the world. In the U.S., about 224,000 people a year get lung cancer. 19 percent of 224,000 is 43,000 people … a year … in the U.S. alone.

Currently, about 160,000 people a year die of lung cancer each year. We’re talking about potentially cutting that number by 25 percent if this drug works as well as promised.

From the NBC story:

Most of the patients helped by Keytruda saw their cancer stop growing for about an average of a year, and some still haven’t had the cancer come back, Garon’s team said in their report, which was also published in the New England Journal of Medicine.

About a quarter of the lung cancer patients in the trial had a mutation in PD-L1, and the people helped most by the drug were more likely to have the mutation, the researchers found.

The drug, known generically as pembrolizumab, caused many side-effects, such as fatigue and rash. But so does chemotherapy for lung cancer.

In a second study, researchers compared Keytruda to another immunotherapy drug called Yervoy in 830 patients with melanoma.

After a year, 74 percent of patients who received Keytruda every two weeks were alive. This dropped to 68 of those dosed every three weeks. To compare, 58 percent of patients who got Yervoy lived a year or longer, researchers reported.

It’s not a cure. Another one of many, many baby steps toward a cure to the Plague of the 20th Century.