By Admin at 1 Jun 2016, 12:57 PM
In 2014, the U.S. Food and Drug Administration (FDA) approved the immunotherapy drug pembrolizumab (brand name Keytruda®) for people with melanoma that cannot be removed by surgery or that has spread to other parts of the body.
The drug was approved under an accelerated fast-track process because of positive initial results from a clinical trial. The end results of that study, published in JAMA, have now been released and confirm the drug’s promise for late-stage melanoma patients.
It involved 655 people with advanced melanoma who were given different doses of the drug (10 mg/kg of body weight every 2 weeks, 10 mg/kg every 3 weeks, or 2 mg/kg every 3 weeks).
Among those who had not been previously treated, 45 percent showed a positive response to pembrolizumab, also known as pembro. After one year, 52 percent had no tumor progression and 60 percent survived at least two years.
Among people who had received prior treatment, 33 percent responded favorably to the drug and 35 percent had no tumor progression after one year.
The drug works by helping the patient’s immune system recognize and attack tumors, which are made of previously normal cells that grow abnormally. The immune system often has difficulty recognizing tumors as invaders, so the tumor cells are able to grow unchecked.
Pembro removes the tumor’s shield so the patient’s immune system can wage an attack. Study author Dr. Antoni Ribas, professor medicine at University of California, Los Angeles, told Time:
“Patients respond to these drugs because their immune system is ready to go, but the tumor is protecting itself … For those patients, we just need to unleash the immune system.”
More research is needed to determine why some patients do not respond to pembro and whether combination drug cocktails may lead to better outcomes in such cases. Pembro is also being studied in the treatment of other types of cancer, including a rare form of virus-caused skin cancer called Merkel cell carcinoma.
Similar to its use in melanoma, pembro appears to be effective at exposing the cancer-causing virus to patients’ immune systems, allowing the immune system to launch an attack. In research published in the New England Journal of Medicine, more than half (56 percent) of patients responded to the drug and 67 percent had no cancer progression for six months.
The initial study was small (just 26 people took part), so researchers are hoping to expand the trial as well as look at pembro’s potential role in other virus-related cancers, such as HPV, Epstein Barr, certain lymphomas and stomach cancers.
It’s an exciting area of research and one that has the potential to change the future of cancer treatment, as researchers increasingly learn how to harness patients’ own immune systems to treat different types of cancer.
Sources:
JAMA April 19, 2016
New England Journal of Medicine April 19, 2016
Time April 19, 2016
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