Colon cancer recovery shows success of immunotherapy
The remarkable recovery of a woman with advanced colon cancer, after treatment with cells from her own immune system, may lead to new options for thousands of other patients with colon or pancreatic cancer, researchers are reporting.
Her treatment was the first to successfully target a common cancer mutation that scientists have tried to attack for decades. Until now, that mutation has been bulletproof, so resistant to every attempt at treatment that scientists have described it as “undruggable.”
An article about the case, from a team led by Dr. Steven Rosenberg, chief of surgery at the National Cancer Institute, was published on Wednesday in The New England Journal of Medicine.
The patient, Celine Ryan, 50, an engineer, database programmer and the mother of five, has an unusual genetic makeup that allowed the treatment to work. She is now cancerfree, though not considered cured.
‘Huge implications’
The treatment was a form of immunotherapy, which enlists a patient’s immune system to fight disease. The field is revolutionizing cancer treatment.
An experiment on one patient cannot determine whether a treatment will be effective in others, but doctors said the results had the potential to help more people.
“It has huge implications,” Dr. Carl June, of the University of Pennsylvania, said in an interview. He was not part of the study, but wrote an editorial accompanying it in the journal.
June said the research was the first successful targeting of a defect in a gene called KRAS, and is important because mutations in the gene are so common. “Every single pancreatic cancer patient has KRAS,” June said, adding that the pharmaceutical industry has spent billions trying to target KRAS.
Still, he said, the big question is whether this case is “one in a million, or something that can be replicated and built upon?”
About 53,000 cases of pancreatic cancer are expected in the United States this year, and nearly 42,000 deaths. It is one of the deadliest cancers; fewer than 10 percent of patients survive five years. Worldwide, it killed about 330,000 people in 2012, the most recent year with global statistics available.
From 30 percent to 50 percent of colorectal cancers have KRAS mutations, too, and about 13 percent have the same mutation that Ryan has. In the U.S., about 95,000 cases of colon cancer and 39,000 cases of rectal cancer are expected in 2016, and 49,000 deaths from the two forms combined. Globally, there were 1.4 million cases and 694,000 deaths in 2012.
Persistent patient
The new discovery might not have been made — at least, not now — without Ryan’s persistence. Researchers twice denied her request to enter the clinical trial, saying her tumors were not large enough, she said. But she refused to give up and was finally let in.
The research involves cancer-fighting immune cells called tumor-infiltrating lymphocytes, or TILs. These are white blood cells that swarm around tumors, a sign that the immune system is trying to attack the cancer. Rosenberg has been studying TILs for decades, with the goal of enhancing their ability to fight the disease and using them as a treatment.
An attempt to treat another patient with tumors much like Ryan’s did not work, almost certainly because the researchers could not produce enough highly targeted TILs, Rosenberg said.
So far, the cells have worked best against advanced melanoma, a deadly form of skin cancer. By extracting TILs from tumors, multiplying them in the lab and then returning them to the patient, Rosenberg’s team has produced long remissions in 20 percent to 25 percent of patients with that disease.