Jimmy Carter, 91, just announced that scans show no cancer in his body, an amazing diagnosis after having a melanoma that had metastasized to his brain and liver. A key part of his treatment was the new drug Pembrolizumab, also known by the Merck brand name Keytruda. How does it work? And does it offer hope for other types of cancer?
Here’s what you need to know.
1. Pembrolizumab Was Fast-Tracked Last Year After Producing Startling Results
Pembrolizumab was fast-tracked last year after receiving “breakthrough therapy designation” from the FDA. The drug was part of Carter’s treatment regimen, which also included targeted radiation to his brain. He may not be cured in the classic sense of the word, and may continue to require infusions, but his MRI scans show no sign of cancer in his body. This is after he revealed that he had cancer in four spots on his brain earlier this year.
2. The Drug Unleashes the Power of the Patient’s Immune System to Fight Cancer
The drug, also known under the brand name Keytruda, works as part of Merck’s immunotherapy system for fighting cancer. It’s the first of a new class of drugs that use the power of the human immune system to fight melanoma that’s spread through the body. Our immune system, when healthy, already fights off a number of cancer cells we never even know about. This drug helps kick that immune system into high gear.
Pembrolizumab targets the PD-1 and PD-L genes, NBC News reported. These two genes play a role in helping tumors escape detection by our immune system. Pembrolizumab is typically used for advanced melanoma when the medicine ipilimumab isn’t working or when the tumor has an abnormal BRAF gene, Yahoo! News reported.
Dr. Wally Curran of Emory University told NBC News about the drug:
It’s really a whole new class of therapy, and as president Carter said, it really allows our own immune system to fight a cancer…”
Antoni Ribas, a researcher at the University of California at Los Angeles, told The Washington Post that these types of treatments are just “taking away the brakes on the immune system.”
3. The Side Effects Are Far Less Harsh Than Chemotherapy
Chemotherapy has terrible side effects because the patient is essentially subjected to a type of poison in order to kill the cancer. But pembrolizumab is different. Side effects for this drug can include fatigue and rash. For Carter, the effects were slight: He had a slight reaction to the infusion, some pain in his shoulder, and he slept well the night after his infusion, NBC News reported. The treatments are also easier, consisting of a 30-minute infusion that doesn’t make you nauseated and isn’t toxic.
4. Treatment Can Cost $150,000 a Year
Carter is not officially “cured” of cancer, even though there is no sign of it in his body according to his last MRIs. Carter will continue to get infusions of pembrolizumab every three weeks. Keytruda can be expensive, costing about $150,000 a year, The Washington Post reported.
5. Keytruda Is Being Studied for Use with Other Cancers
Pembrolizumab isn’t just used for metastasized melanoma. It’s also prescribed for certain types of lung cancers, such as non-small cell lung cancer that has spread, especially if the cancer tests positive for PD-L1 and certain chemotherapies don’t work, Yahoo! News reported. Outside of the U.S., Keytruda is launching in around 40 markets, including the EU. Keytruda’s program is studying the drugs use in 30 different types of tumors and more than 160 clinical trials.
In December, Keytruda was granted breakthrough therapy status by the FDA for treatment of certain metastasized colorectal cancers, Oncology Times reported. Because Keytruda works so well on cancers with a PD-1/PD-L1 pathway, it might also be a potential future treatment for people suffering from mesothelioma-related cancers.
Immune therapies in general are being tested on bladder cancer, breast cancer, Hodgkin’s lymphoma, head and neck tumors, and other diseases, The Washington Post reported. Melanoma is the cancer with the greatest response so far. Some people respond immediately, with their tumors vanishing within weeks. Some had only weeks to live and now are returning to their lives, cancer free.