After 40 years of effort, researchers have finally succeeded in switching off one of the most common cancer-causing genetic mutations in the human body.
A new medication, Sotorasib, produced by U.S. drugmaker Amgen, attacks cancer-causing mutation, known as KRAS G12C, that occurs in 13 percent of patients, almost all of whom are current or former smokers.
Sotorasib made the cancers shrink significantly in patients with the mutation, Amgen reported last week at the World Conference on Lung Cancer.
On average, tumors in the patients stopped growing for seven months. In three out of 126 patients, the drug seems to have made the cancer disappear entirely, at least so far, although side effects included diarrhea, nausea and fatigue.
It already is routine to test lung cancer patients for the mutation, because they are often resistant to other drugs, said Dr. John Minna, a lung cancer specialist at the University of Texas Southwestern Medical Center in Dallas.
Amgen’s drug is not as drastically effective as some new cancer medicines, said Dr. Bruce Johnson, the chief clinical research officer at the Dana-Farber Cancer Institute in Boston.
But in combination with other drugs, those targeting specific mutations can change the course of the disease in many patients, he added.
For example, drugs targeting specific mutations in melanoma patients at first seemed unimpressive, but when combined with other medicines, they eventually changed prospects for patients with this deadly disease.
“The more I looked at it, the more optimistic I became,” Dr. Johnson said of Amgen’s new data.
While the KRAS G12C muttumours is most common in lung cancer, it also occurs in other cancers, especially in colorectal cancer, where it is found in up to 3 percent of tumors, and particularly in pancreatic cancer. KRAS mutations of some type are present in 90 percent of pancreatic tumors.
How the off-switch was discovered is a story of serendipity and persistence by an academic chemist who managed the seemingly impossible.
