According to a groundbreaking new study, a dose of Keytruda before surgery could stop cancer for people with fatal melanoma skin cancer.
Keytruda (pembrolizumab) is an inhibitor of PD-1, an immunotherapy drug that triggers the body's immune response to attack cancer cells. According to the results of this study, the effects of the drug peak seven days after treatment, much earlier than in other studies.
In addition, patients who had benefited from this immunotherapy for one year after surgery were free from their cancer for more than two years, the longest follow-up to date on patients with melanoma.
"The anti-PD-1 acts extremely rapidly, immunological responses reaching their maximum in most patients in the space of one to three weeks," said co-author of the 39, study, John Wherry. He is director of the Penn Institute for Immunology at the University of Pennsylvania.
About a third of patients were "essentially cured in three weeks, highlighting the speed of immunotherapy for cancer," said Wherry.
And in patients whose cancer has recurred, researchers have found revealing patterns of how cancer adapts to the drug – discoveries that could provide better ways to treat such patients.
Keytruda is the drug responsible for the remission of cancer of former President Jimmy Carter in 2015. Carter, then 90, had a melanoma that had spread to the brain and liver. A treatment with Keytruda seems to have healed him.
The drug is not cheap, it costs around $ 150,000 a year. Keytruda is covered by most insurance, including health insurance, but copays can be high, according to the Kaiser Family Foundation.
For the study, researchers administered a single dose of Keytruda to 27 patients with advanced melanoma three weeks before surgery.
Eight patients presented what the researchers described as a complete response, meaning that only 10% of the cancer cells remained at the time of surgery. All eight remained cancer-free until 25 months of follow-up.
The researchers also studied how tumor cells in patients whose cancer had recurred could develop resistance to Keytruda. The researchers discovered two causes: tumor mutations and increased cell activity that naturally suppress the immune system.
Knowing the factors that lead to a lack of drug response can help identify patients who may benefit from other treatments in combination with PD-1, Wherry said.
Dr. Steven Savona, a physician at the Mountwell Cancer Treatment Center in Lake Success, N.Y., did not participate in the study, but reviewed the results. He added that the fast-acting immune response offers a new approach to a disease that was only accessible by surgery.
Savona said that this could simplify surgery and that in case of association with other treatments, the surgery might not even be necessary for some patients.
"This could be a new approach for patients with limited but advanced melanoma, but we need additional tests to prove it," said Savona.
Merck, Inc., a manufacturer of Keytruda, provided the drug for the study but did not fund the trial.
Melanoma is the most lethal form of skin cancer. The American Cancer Society estimates that more than 96,000 new melanomas will be diagnosed in the United States this year and 7,200 people will die from this disease.
Standard treatment includes surgery followed by one-year drug treatment in high-risk patients.
The report was published Feb. 25 in the journal Nature Medicine.
The American Cancer Society offers more facts about melanoma.
Copyright © 2019 HealthDay. All rights reserved.