How Patients’ Own Cells are Treating — and Sometimes Curing — Their Cancer
Article Summary
- CAR T-cell therapy involves engineering a patient’s own immune cells to recognize and attack their tumors.
- Cell therapies are extending the lives of patients with many of the most common forms of blood cancers.
- Sylvester researchers are working to improve and expand the therapies on multiple fronts.
It sounds like something almost too futuristic to be true: A cancer patient’s cells are extracted from their body, engineered in the lab to carry a gene never before seen in nature and then put back in the patient’s body, where these souped-up cells then go after and eliminate tumors.
Meet cell therapy, a form of cancer immunotherapy that can transform a patient’s own immune cells to become efficient, cancer-fighting machines.
Since 2017, when the first cell therapy was approved by the FDA for the treatment of acute lymphoblastic leukemia, cell therapy has become a reality for many patients with the most common forms of blood cancers. Cell therapies have since been approved for lymphomas, other forms of leukemia, multiple myeloma, metastatic melanoma and metastatic synovial sarcoma.
Physicians and scientists, including those at Sylvester Comprehensive Cancer Center, a part of the University of Miami Miller School of Medicine, are also working to make these futuristic technologies real for more patients, including those with other solid tumors and for diseases other than cancer.
“We have seen dramatic responses by harnessing the power of the immune system,” said Damian Green, M.D., chief of Sylvester’s Division of Transplantation and Cellular Therapy and assistant director of translational research at the Miller School. “It’s a huge shift in terms of what we can do to benefit patients and leverage new science.”
Freeing the Immune System to Do Its Work
One of the most promising forms of cell therapy is known as CAR T therapy, in which a type of immune cell known as a T cell is engineered with a gene that gives it a new kind of receptor, a chimeric antigen receptor, or CAR. This human-designed receptor allows the engineered cells to home to and attack cancer cells by recognizing specific proteins on the surface of cancer cells.
Another form of cell therapy, tumor-infiltrating lymphocyte therapy (the type recently approved for melanoma), involves extracting a patient’s immune cells that naturally recognize tumors and growing them to large numbers in the lab before reinfusing them back to the patient. All FDA-approved cell therapy products are available to Sylvester patients. Clinical trials at the center also give patients access to experimental therapies not yet broadly available.
Cell therapy takes advantage of the immune system’s natural power, evolved over the course of human evolution to protect us from harm, which may be why it shows such dramatic effects. Although the treatments still don’t work for all patients, they have given many people who were out of options more time with their loved ones — and, in some cases, may have even cured their cancers completely.
“Unlike synthetic cancer drugs that we put into a patient, which have virtually all been developed in the last 100 years, the immune system has evolved since long before the first hominids walked the Earth,” Dr. Green said. “In fact, we are harnessing the power of an adaptive immune system whose beginnings date back at least 450 million years.”
Although the treatments have some side effects, they can be safe and effective in many patients. Patients in their 80s and even early 90s have been successfully treated at Sylvester with cell therapy.
How the Pioneers of a Field Felt
Denise Pereira, M.D., associate professor of clinical medicine in the Division of Transplantation and Cellular Therapy at Sylvester, has been treating blood cancer patients for many years. She’s also a history of medicine buff and pored over the original papers describing chemotherapy treatments. She remembers thinking how the authors knew they were onto something big, a game-changer for cancer medicine, even as they also recognized the limits of the treatment.
Dr. Pereira was part of the team that treated the first Sylvester patient with CAR T therapy through one of the early trials that led to the treatment’s approval.
“When I saw the results of that first treatment, I thought to myself, ‘I’m feeling what the pioneers of the chemotherapy field felt decades ago when they started to use chemotherapy,’” Dr. Pereira said. “It struck me what this actually could mean for our patients. It meant that patients could be potentially cured, and it also meant that patients could experience things like their kids’ graduations or marriages that they otherwise would have missed.”
The Future of Cell Therapy
Although CAR T therapy is extending many blood cancer patients’ lives, it’s not a perfect cure-all. Many patients who receive this treatment eventually relapse. For some cancer types, nearly all see their cancer come back eventually. Researchers are working to understand why so they can stop those relapses and work toward true cures for more patients.
While many research teams are tackling the improvement of CAR T cells themselves, Jonathan Schatz, M.D., professor of medicine in the Division of Hematology at Sylvester, is working to understand the other side of the equation when these therapies fail: the characteristics of tumors that contribute to resistance. His laboratory team is analyzing lymphoma tumor genetics to find resistance-associated mutations, with the goal of designing treatments that could overcome that resistance.
“The more we know about the way cell therapies work, the more information it provides for the field to make cell therapy better,” Dr. Schatz said.
Researchers are working on two large areas: Improving existing CAR T products so they work for more patients and developing new products to expand the therapy’s reach to more diseases.
Each CAR is designed to recognize a specific protein present on cancer cells’ surfaces. Many of those proteins are unique to specific types of cancer. Picking and testing the correct target can be a complicated process, but research groups, including those at Sylvester, are working on developing and testing a variety of different kinds of CAR T cells for different cancers, including many solid tumors. Recent trials at the center have tested cell therapies in breast and lung cancers.
Many of Sylvester’s cell therapy trials are investigator-initiated trials. Sylvester researchers drive the innovation behind the trial. The center is also a site for many multi-center trials led by industry partners or teams at other universities.
Sylvester researchers are also working to broaden the therapy’s approach beyond cancer. Dr. Pereira is part of a team testing CAR T therapies to treat neurological autoimmune disorders, including multiple sclerosis and myasthenia gravis. Other teams at the University of Miami are working on CAR T therapy for lupus.
Improving Access for Cancer Patients
Beyond new innovations for cell therapy, Sylvester is also working to expand access to existing therapies to more patients. Currently, the center’s cell therapy lab, led by Cara Benjamin, Ph.D., a researcher assistant professor in the Division of Transplantation and Cellular Therapy at Sylvester, processes cells after they’re extracted from patients. But the engineering happens off-site at specialized facilities. The group is now working on adding the capability to engineer T cells onsite at Sylvester, which would expand their capacity to treat more patients and reduce the time patients need to wait for their treatment to be ready.
They’re also gearing up to offer the treatment on an outpatient basis, where appropriate. Currently, patients stay in the hospital so their care teams can monitor side effects. But as methods to prevent toxicities associated with the therapies have improved, some centers are moving toward shorter stays or outpatient care.
“Understanding how to harness and utilize a patient’s own immune system to treat their conditions is a limitless endeavor,” said Dr. Benjamin. “We’re just starting to tap into some of the things that are possible.”
Tags: breast cancer, cancer research, CAR T cells, Dr. Cara Benjamin, Dr. Damian Green, Dr. Denise Pereira, Dr. Jonathan Schatz, living cell therapy, lung cancer, multiple myeloma, Sylvester Comprehensive Cancer Center