Investing in CAR T-cell therapy to treat cancer

Photo credit: UC Regents 

The California Institute for Regenerative Medicine (CIRM) is investing $4 million to support Dr. William Murphy and UC Davis researchers to develop and test a chimeric antigen receptor (CAR) T-cell therapy to treat various B-cell malignancies, ranging from lymphomas to leukemias. 

In this Q&A—courtesy of UC Davis Health—Dr. Murphy discusses the importance of T-cell therapy and its implications for developing cancer treatments. His work is a collaboration between CIRM, the nonprofit organization Caring Cross, and UC Davis Health. 


What are B-cell malignancies? 

B-cells are a type of white blood cells that make antibodies. They are key to the body’s immune system. When healthy B-cells change into fast-growing cancer cells that don’t die, they cause B-cell malignancies. 

This can affect people at different ages. They may show up in children as B-cell acute lymphoblastic leukemia (B-ALL), an aggressive blood and bone marrow cancer. In adults, they make up about 85% of non-Hodgkin lymphoma (NHL), a cancer that starts in B lymphocytes. In the elderly, B-cell malignancies may come as multiple myeloma, a cancer of the plasma cells. 

There are different lines of treatments for B-cell lymphoma and leukemia, including immunotherapy using chimeric antigen receptor (CAR) T cells. These cells have revolutionized cancer treatment since they have been shown to work, and cure, when nothing else can. 

What is chimeric antigen receptor (CAR) T-cell therapy? 

Chimeric antigen receptor (CAR) T-cell therapy uses the body’s own defenses to fight disease. It is a new and exciting form of immunotherapy that works by modifying the receptors of immune cells (T cells) involving antibodies to target specific cancers, such as leukemias and lymphomas. 

CAR T cells are being used to treat some blood cancers with long-term success. The U.S. Food and Drug Administration (FDA) first approved CAR T-cell therapy in 2017. Their use is growing rapidly and being applied to other tumor types. Yet, this therapy is extremely expensive, even with insurance. It’s also a very intensive procedure and it takes time to generate the CAR T cells from the patient. 

While it could be considered a game changer, one of the issues with this therapy is the case relapse rate. The big holy grail in cancer therapy is how to prevent tumors from evading or escaping the immune attack. Around 60% of patients who get CAR therapy see their cancer return. If we can get the relapse rate down to negligible, that would be a tremendous advance. 

How do you intend to use CAR products to reduce cancer relapse? 

In CAR therapy, we take the immune T cells from a patient and use gene therapy to give a new receptor to signal and direct the T cell. The receptor usually has an antibody that recognizes a particular tumor antigen. Current FDA-approved CAR T therapies only target one tumor antigen. 

CARs have had tremendous success. However, there is significant patient relapse because the tumor adapts and may lose that one antigen that we are targeting, allowing it to escape the treatment. Our strategy is to target multiple antigens to reduce the potential for relapse since the tumor cannot adapt that quickly. 

We are also proposing a novel vector that will carry a CAR product, known as DuoCAR, that targets three antigens at the same time. As long as the tumor has one of the three antigens, then there’s little chance for the tumor to escape all three antibodies. This is similar to when you think about HIV treatment with the triple-drug therapy, where one alone is not sufficient. 

The hope is that the 60 to 70% of the population who would have relapsed if they had the original CAR T cell treatment, would have a home run with our kind of treatment or product. 

So, is this treatment for cancer patients who have relapsed? 

We see this product as a new frontline therapy and not just for patients who relapse. What the patient has to go through in order for CAR T therapy to work is very strenuous. So, yes, if there are relapsed patients, they can be given DuoCAR, but we’re also hoping this will become the new standard of care, replacing the other CARs in the future for everyone. 


To read the full Q&A, click here

UC Davis Health researchers aim to use CAR T cells for HIV cure

Dr. Abedi (right) in the lab at UC Davis Health. He and his team of researchers have launched a study looking to identify a potential cure for HIV. Photo Courtesy of UC Davis Health.

Worldwide, almost 38 million people are living with HIV—the virus that can lead to AIDS— and it’s estimated that 75% of them receive antiviral treatment to keep the virus in check. In California, 150,000 people live with HIV and 68% of these individuals are virally suppressed due to treatment.  

To fight this virus, UC Davis Health researchers—with funding from a CIRM grant—have launched a study looking to identify a potential cure for HIV. Using immunotherapy, researchers will take a patient’s own white blood cells, called T-cells, and modify them so that they can identify and target HIV cells to control the virus without medication. 

Targeting HIV with CAR T cells

“For this study we will educate the cells by inserting a gene to target cells that have been infected by the HIV virus,” explained Mehrdad Abedi, professor of internal medicine, hematology and oncology and the principal investigator of the study. “The idea is these modified cells will attach to the HIV-infected cells and destroy the cells that are infected while also stopping the infected cells’ ability to replicate.” 

Modified T-cells, known as CAR T cells, are an FDA-approved treatment for different forms of cancer including acute lymphoblastic leukemia, non-Hodgkin lymphoma, and multiple myeloma. With cancer, the immune system often fails to deploy T-cells right away or at all. When it does, the attack is ineffective. CAR T-cell immunotherapy changes these collected T-cells to produce chimeric antigen receptors (or CARs) that adhere to tumors to destroy them. 

Study seeking HIV patients

For the study, UC Davis Health researchers are working to identify and recruit HIV-positive patients between the ages of 18 and 65 who have had an undetectable HIV viral load for the 12 months and have been on continuous antiretroviral therapy for at least 12 months.  

Patients also need to be willing to pause their antiretroviral therapy as part of the study. 

“While it is exciting, the study will require a lot of dedication from the patient because of the time commitment involved and the necessary steps required,” said Paolo Troia-Cancio, a clinical professor of medicine with the infectious disease division with over 20 years of experience treating HIV and co-investigator on the CAR T cell study.   

The search for an HIV cure 

Three patients have been cured of HIV using bone marrow transplants, including a woman in New York who received a cord blood stem cell transplant. She received a bone marrow transplant using umbilical cord blood donor cells that bore a mutation that makes them resistant to HIV infection to treat her leukemia. 

There have also been two previous cases involving an HIV cure following allogeneic bone marrow transplants. Both patients had leukemia and received bone marrow transplants from donors who carried the same mutation that blocks HIV infection.  

“While these stories provide inspiration and hope to finding a cure for HIV, a bone marrow transplant is not a realistic option for most patients,” said Abedi. “Such transplants are highly invasive and risky, so they are generally offered only to people with cancer who have exhausted all other options.” 

Abedi and his fellow researchers see this study as a potential road map to finding a cure for HIV.  

The California Institute for Regenerative Medicine (CIRM) has funded earlier work by Dr. Abedi and his team in trying to develop a therapy to help people with HIV who also have lymphoma.  

To read the source article about this CIRM-funded study, click here

Stem cell byproducts provide insight into cure for spina bifida

A diagram of an infant born with spina bifida, a birth defect where there is an incomplete closing of the backbone portion of the spinal cord. Photo courtesy of the Texas Children’s Hospital website.

Some of you might remember a movie in the early 2000s by the name of “Miracle in Lane 2”. The film is based on an inspirational true story and revolves around a boy named Justin Yoder entering a soapbox derby competition. In the movie, Justin achieves success as a soapbox derby driver while adapting to the challenges of being in a wheelchair.

Scene from “Miracle in Lane 2”

The reason that Justin is unable to walk is due to a birth defect known as spina bifida, which causes an incomplete closing of the backbone portion of the spinal cord, exposing tissue and nerves. In addition to difficulties with walking, other problems associated with this condition are problems with bladder or bowel control and accumulation of fluid in the brain.

According to the Center for Disease Control (CDC) , each year about 1,645 babies in the US are born with spina bifida, with Hispanic women having the highest rate of children born with the condition. There is currently no cure for this condition, but researchers at UC Davis are one step closer to changing that.

Dr. Aijun Wang examining cells under a microscope. He has identified stem cell byproducts that protect neurons. Photo courtesy of UC Regents/UC Davis Health

Dr. Aijun Wang, Dr. Diana Farmer, and their research team have identified crucial byproducts produced by stem cells that play an important role in protecting neurons. These byproducts could assist with improving lower-limb motion in patients with spina bifida.

Prior to this discovery, Dr. Farmer and Dr. Wang demonstrated that prenatal surgery combined with connective tissue (e.g. stromal cells) derived from stem cells improved hind limb control in dogs with spina bifida. Below you can see a clip of two English bulldogs with spina bifida who are now able to walk.

Their findings were published in the Journal of the Federation of American Societies for Experimental Biology on February 12, 2019.

The team will use their findings to perfect the neuroprotective qualities of a stem cell treatment developed to improve locomotive problems associated with spina bifida.

In a public release posted by EurekaAlert!, Dr. Wang is quoted as saying, “We are excited about what we see so far and are anxious to further explore the clinical applications of this research.”

The discovery and development of a treatment for spina bifida was funded by a $5.66 million grant from CIRM. You can read more about that award and spina bifida on a previous blog post linked here.