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

Pioneering a new approach to HIV/AIDS

Dr. Steven Deeks. Photo courtesy UCSF

I’ve always been impressed by the willingness of individuals to step forward and volunteer for a clinical trial. Even more so when they are the first person ever to test a first-in-human therapy. They really are pioneers in helping advance a whole new approach to treating disease. 

That’s certainly the case for the first individual treated in a CIRM-funded clinical trial to develop a functional cure for HIV/AIDS. Caring Cross announced recently that they have dosed the first patient in the trial testing their anti-HIV duoCAR-T cell therapy.  

The trial is being led by UC San Francisco’s Dr. Steven Deeks and UC Davis’ Dr. Mehrdad Abedi. Their approach involves taking a patient’s own blood and extracting T cells, a type of immune cell.  The T cells are then genetically modified to express two different chimeric antigen receptors (CAR), which enable the newly created duoCAR-T cells to recognize and destroy HIV infected cells.  The modified T cells are then reintroduced back into the patient. 

The goal of this one-time therapy is to act as a long-term control of HIV with patients no longer needing to take anti-HIV medications. If it is successful it would be, in effect, a form of functional HIV cure.   

This first phase involves giving different patients different levels of the duoCAR-T therapy to determine the best dose, and to make sure it is safe and doesn’t cause any negative side effects.  

This is obviously just the first step in a long process, but it’s an important first step and certainly one worth marking. As Dr. Deeks said in the news release, “We have reached an important milestone with the dosing of the first participant in the Phase 1/2a clinical trial evaluating a potentially groundbreaking anti-HIV duoCAR-T cell therapy. Our primary goal for this clinical trial is to establish the safety of this promising therapeutic approach.” 

Dr. Abedi, echoed that saying. “The first participant was dosed with anti-HIV duoCAR-T cells at the UC Davis medical center in mid-August. There were no adverse events observed that were related to the product and the participant is doing fine.” 

This approach carries a lot of significance not just for people with HIV in the US, but also globally. If successful it could help address the needs of people who are not able to access antiretroviral therapies or for whom those medications are no longer effective.  

Today there are an estimated 38 million people living with HIV around the world. Every year some 650,000 people die from the disease.