Among the ongoing efforts to increase success rates in treating cancer, immunotherapy continues to gain a big part of the attention. Here are five things to know about this promising treatment area.
1. Activity related to immunotherapy is on the upswing. “Immunotherapy is having a renaissance in oncology,” says Timothy Byun, MD, an oncologist with the Center for Cancer Prevention and Treatment at St. Joseph Hospital in Orange, California. He notes that many clinical trials are under way involving immunotherapy, and more and more treatments are being approved by the FDA for various cancer conditions. “It's clear to many of us oncologists that immunotherapy is becoming an integral part of cancer therapy,” he says.
2. Work with checkpoint inhibitors seems to be leading the way. Immune checkpoint inhibitors (a class of molecules which inhibit PD-1 or PD-L1 or CTLA-4 proteins which are involved in inhibitory immune regulation) have made the most impact in cancer treatment in recent years, according to Byun. In fact, the 2018 Nobel Prize in Medicine was awarded to researchers in recognition of their work on CTLA-4 and PD-1 molecules.
“Immunotherapy with the newer anti PD1 and anti PDL1 drugs is changing the practice of oncology,” says Charles Redfern, MD, medical director of medical oncology for Sharp HealthCare's Laurel Amtower Cancer Institute and Neuro-Oncology Center in San Diego. “These therapies have dramatically changed the treatment and prognosis of advanced melanoma, advanced kidney cancer, and advanced lung cancer.”
Byun says that current studies involving immune checkpoint inhibitors (IOs) include those combining IO and IO; IO and chemotherapy; IO and molecular targeted therapy; IO and surgery; and IO and radiation therapy.
3. CAR T-cell therapy is also generating excitement. With this type of immunotherapy, T lymphocytes from a patient’s blood are genetically modified in a laboratory setting and then re-infused, bringing an increased capacity for recognizing and attacking cancer cells. Byun notes that this approach is now FDA approved for certain blood cancer subtypes, with more indications for various cancers expected in the near future.
“Currently, this therapy is restricted to only specialized centers due to toxicity issues as well as cost issues,” he says. “But we expect that with continued refinement of this technology, it will be readily available to many centers in future.”
4. Other strategies under the immunotherapy umbrella are also being pursued. One that has been in play for some time is the use of monoclonal antibodies. Under this approach, researchers design antibodies that specifically target a given antigen and then make multiple copies, designated as monoclonal antibodies (mAbs), which can be used to treat some types of cancer. More than a dozen mAbs have been approved by the FDA over the past couple of decades to treat cancer, according to the National Cancer Institute. Other approaches range from treatment vaccines to cytokines such as interferons and interleukins, which enhance the body’s immune response to fight cancer
5. Significant challenges remain. “As much as there is excitement about immunotherapy, there are still many challenges we are facing,” Byun says. He notes that while immunotherapy has benefited many patients, only a minority of cancer sufferers respond to the therapy. And at this point, physicians are still trying to understand how to predict which patients will respond well. Another major concern is cost, in some cases reaching the hundreds of thousands of dollars.
“We hope that continued innovation and better understanding of cancer and immunotherapy, as well as a robust free-market competition to drive down the cost, would help to contain the cost while helping our cancer patients to live longer and with better quality of life,” Byun says.