Woman's Own Immune System Helps Fight Cancer
(NEW YORK) -- At first, Candace Brown didn’t think too much of the large, lumpy bruise that spontaneously appeared on her leg about a year ago. But when it didn’t heal after a couple of weeks, she decided to get it checked out. Even though her primary care physician told her not to worry, she pushed for a biopsy. The “bruise” was diagnosed as a skin melanoma.
Doctors told the 44-year-old teacher and mother of two that the cancer had already spread to her lungs and lower intestine, a prognosis she said left her feeling terrified and bewildered. When she was told her condition had a five-year survival rate, she stopped listening.
“I refused to hear it,” Brown recalled. “I decided I would do my own research and see what was out there for me that could help.”
Almost immediately, Brown caught a lucky break. A quick review of clinicaltrials.gov, a website run by the United States National Library of Medicine, found a study for a new approach to treating melanoma at the Georgetown University Lombardi Comprehensive Cancer Center in Washington, D.C. Brown lives in Maryland, so the trial was being held right in her own backyard.
Instead of chemotherapy, the trial relied on something called immune-checkpoint blockade, a form of immunotherapy. Patients receive medicine that trains their own immune system to rally against cancer with the aid of specialized proteins known as monoclonal antibodies.
Dr. Michael Atkins, the medical oncologist who led the trial and who is also the deputy director of the Lombardi Center, explained that patients are often unable to battle cancer because tumors successfully block the body’s immunoresponse to them. When this happens, tumors can continue spreading and growing without any resistance from the body’s healthy cells. Immune-checkpoint blockade aims to rouse the immune system so it has the strength to do an end run around cancer’s blocking techniques and fight against the disease.
“The antibodies take the brakes off the immune system’s response to a tumor,” Atkins explained. “They unblock the reaction that stops the immune system’s natural attack on invading cancer cell so the body can fight the cancer.”
Brown was accepted into the trial which used a combination of two immune-stimulating drugs, drugs PD1 inhibitor and ipilumumab, to ramp up the body’s natural defense mechanisms. Every few weeks for three months, she endured a five-hour session hooked up to an intravenous drip which she said was similar to chemotherapy but with fewer side effects. In the first part of the trial two drugs were delivered into her bloodstream, then in later sessions just the ipilumumab.
Brown’s initial scan at the end of the trial revealed that most of the tumors had shrunk in size. Many of them were gone. The follow up scan done several weeks after the trial was completed showed no discernable signs of cancer. When Brown saw the scans, they brought tears of relief and joy.
“After the first scan I was dubiously optimistic, but after the second scan, I was overwhelmed. It felt like I was being given a second chance,” she said.
Atkins cautioned that, although Brown seems to be one of the lucky ones, it’s too soon to tell whether her cancer is gone forever. It’s also too early to say whether immunotherapy will be the miracle breakthrough in cancer treatment that everyone hopes for. About half the patients in the trial saw no improvement.
“The next step will be to determine why it isn’t effective for certain patients and figure out a way to make it work for them. Right now therapies use a patient’s own immune system to recognize a tumor, but they can’t yet be customized for each unique immune system or cancer,” he said.
Currently, at least seven drug companies are testing some form of immunotherapy for treating cancer. Atkins said he expected several drugs to be approved for wider use by the end of this year and several more by the end of next year.
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