New CAR-T cell therapy using scorpion venom developed to treat brain tumors

Contributed by Wikimedia Commons (Public Domain)

Glioblastoma (GBM) is an aggressive form of cancer that begins in the brain and results in tumors that can be very difficult to treat. This condition has claimed the lives of Beau Biden, former Vice President Joe Biden’s son, and John McCain, former Senator of Arizona. However, a new approach to combat this condition is being developed at City of Hope and has just received approval from the FDA to conduct clinical trials. The innovative approach involves using a combination of chimeric antigen receptor (CAR)-T cell therapy and specific components of scorpion venom!

Before we dive into how the scorpion venom is being used, what exactly is CAR-T cell therapy?

Diagram of CAR-T Cell Therapy
Image Source: National Cancer Institute

This approach consists of using T cells, which are an immune system cell that can destroy foreign or abnormal cells, and modifying them with a protein called a chimeric antigen receptor (CAR). These newly designed CAR-T cells are able to identify and destroy cancer cells by detecting a specific protein on these cells. What makes CAR-T cell even more promising is that the specific protein detected can be set to virtually anything.

This is where the scorpion venom comes into play. One of the components of this venom is called chlorotoxin (CLTX), which has the ability to specifically bind to brain tumor cells.

Michael Barish, Ph.D. (Left), Christine Brown, Ph.D. (Center), Dongrui Wang (Right)
Photo Credit: Business Wire

For this study, Dr. Christine Brown, Dr. Michael Barish, and a team of researchers at City of Hope designed CAR-T cells using chlorotoxin in order to specifically detect and destory brain tumor cells. Now referred to as CLTX-CAR-T cells, they found that these newly engineered cells were highly effective at selectively killing brain tumor cells in animal models. What’s more remarkable is that the CLTX-CAR-T cells ignored non-tumor cells in the brain and other organs.

In a press release, Dr. Barish describes the CLTX-CAR-T cell approach in more detail.

“Much like a scorpion uses toxin components of its venom to target and kill its prey, we’re using chlorotoxin to direct the T cells to target the tumor cells with the added advantage that the CLTX-CAR T cells are mobile and actively surveilling the brain looking for appropriate target. We are not actually injecting a toxin, but exploiting CLTX’s binding properties in the design of the CAR. The idea was to develop a CAR that would target T cells to a wider variety of GBM tumor cells than the other antibody-based CARs.”

In the same press release, Dr. Brown talks about the promise of this newly developed therapy.

“Our chlorotoxin-incorporating CAR expands the populations of solid tumors potentially targeted by CAR T cell therapy, which is particularly needed for patients with cancers that are difficult to treat such as glioblastoma. This is a completely new targeting strategy for CAR T therapy with CARs incorporating a recognition structure different from other CARs.”

The first-in-human clinical trial using the CLTX-CAR T cells is now screening potential patients.

CIRM has funded a separate clinical trial conducted by Dr. Brown that also involves CAR-T cell therapy for brain tumors.

The full results of this study was published in Science Translational Medicine.

A video talking about this approach can also be found here.

An off-the-shelf cancer killer

iPS Cell: Photo from the lab of Kathrin Plath at UCLA

One of the hottest areas in cancer research right now is the use of CAR-T treatments. These use the patient’s own re-engineered immune system cells to target and kill the tumor. But the thing that makes it so appealing – using the patient’s own cells – also makes it really complicated and expensive. Creating a custom-made therapy from each patient’s own cells takes time and costs a lot of money. But now a new approach could change that.

Fate Therapeutics has developed an off-the-shelf therapy (thanks to CIRM funding) that could, theoretically, be stored at hospitals and clinics around the country and used whenever it’s needed for anyone who needs it.

At this year’s meeting of the American Society of Hematology (ASH) Fate announced that the first patient treated with this new approach seems to be doing very well. The patient had acute myeloid leukemia and wasn’t responding to conventional treatments. However, following treatment with Fate’s FT516 the patient responded quickly and – according to STAT News’ Adam Feuerstein – was able to leave the hospital and spend Thanksgiving with his family.

Equally impressive is that 42 days after being treated with FT516, the man showed no signs of leukemia in either his bone marrow or blood.

FT516 is designed to provide a one-two combination attack on cancer. It’s made up of the wonderfully named natural killer (NK) cells, which are a critical part of our immune system defenses against cancer. These NK cells are created by using the iPSC process and have been genetically modified to express a protein that boosts their cancer-killing abilities.

Because these cells are manufactured they can, if effective, be produced in large numbers and stored for whenever needed. That would not only dramatically reduce costs but also make them more widely available when they are needed.

This is only one patient and the follow-up is still relatively short. Even so, the results are encouraging and certainly give hope that Fate is on to something big. We’ll be keeping track and let you know how things progress.

CIRM Board Approves New Clinical Trial for Breast Cancer Related Brain Metastases

Dr. Saul Priceman

Yesterday the governing Board of the California Institute for Regenerative Medicine (CIRM) awarded $9.28 million to Dr. Saul Priceman at City of Hope to conduct a clinical trial for the treatment of breast cancer related brain metastases, which are tumors in the brain that have spread from the original site of the breast cancer.

This award brings the total number of CIRM-funded clinical trials to 56. 

Breast cancer is the second-most common cancer in women, both in the United States (US) and worldwide.  It is estimated that over 260,000 women in the US will be diagnosed with breast cancer in 2019 and 1 out of 8 women in the US will get breast cancer at some point during her lifetime. Some types of breast cancer have a high likelihood of metastasizing to the brain.  When that happens, there are few treatment options, leading to a poor prognosis and poor quality of life. 

Dr. Priceman’s clinical trial is testing a therapy to treat brain metastases that came from breast cancers expressing high levels of a protein called HER2.   The therapy consists of a genetically-modified version of the patient’s own T cells, which are an immune system cell that can destroy foreign or abnormal cells.  The T cells are modified with a protein called a chimeric antigen receptor (CAR) that recognizes the tumor protein HER2.  These modified T cells (CAR-T cells) are then infused into the patient’s brain where they are expected to detect and destroy the HER2-expressing tumors in the brain.

CIRM has also funded the earlier work related to this study, which was critical in preparing the therapy for Food and Drug Administration (FDA) approval for permission to start a clinical trial in people.

“When a patient is told that their cancer has metastasized to other areas of the body, it can be devastating news,” says Maria T. Millan, M.D., the President and CEO of CIRM.  “There are few options for patients with breast cancer brain metastases.  Standard of care treatments, which include brain irradiation and chemotherapy, have associated neurotoxicity and do little to improve survival, which is typically no more than a few months.  CAR-T cell therapy is an exciting and promising approach that now offers us a more targeted approach to address this condition.”

The CIRM Board also approved investing $19.7 million in four awards in the Translational Research program. The goal of this program is to help promising projects complete the testing needed to begin talking to the US Food and Drug Administration (FDA) about holding a clinical trial.

Dr. Mark Tuszynski at the University of California San Diego (UCSD) was awarded $6.23 million to develop a therapy for spinal cord injury (SCI). Dr. Tuszynski will use human embryonic stem cells (hESCs) to create neural stem cells (NSCs) which will then be grafted at the injury site.  In preclinical studies, the NSCs have been shown to help create a kind of relay at the injury site, restoring communication between the brain and spinal cord and re-establishing muscle control and movement.

Dr. Mark Humayun at the University of Southern California (USC) was awarded $3.73 million to develop a novel therapeutic product capable of slowing the progression of age-related macular degeneration (AMD), the leading cause of vision loss in the US.

The approach that Dr. Humayun is developing will use a biologic product produced by human embryonic stem cells (hESCs). This material will be injected into the eye of patients with early development of dry AMD, supporting the survival of photoreceptors in the affected retina, the kind of cells damaged by the disease.

The TRAN1 awards went to:

Stay tuned for our next blog which will dive into each of these awards in much more detail.

Taking a new approach to fighting a deadly brain cancer

Christine Brown DSC_3794

Christine Brown, Ph.D., City of Hope researcher

CIRM’s 2017 Annual Report will be going live online very soon. In anticipation of that we are highlighting some of the key elements from the report here on the Stem Cellar.

One of the most exciting new approaches in targeting deadly cancers is chimeric antigen receptor (CAR) T-cell therapy, using the patient’s own immune system cells that have been re-engineered to help them fight back against the tumor.

Today we are profiling City of Hope’s Christine Brown, Ph.D., who is using CAR-T cells in a CIRM-funded Phase 1 clinical trial for an aggressive brain cancer called malignant glioma.

“Brain tumors are the hardest to treat solid tumors. This is a project that CIRM has supported from an early, pre-clinical stage. What was exciting was we finished our first milestone in record time and were able to translate that research out of the lab and into the clinic. That really allowed us to accelerate treatment to glioblastoma patients.

I think there are glimmers of hope that immune based therapies and CAR-T based therapies will revolutionize therapy for patients with brain tumors. We’ve seen evidence that these cells can travel to the central nervous system and eliminate tumors in the brain.

We now have evidence that this approach produces a powerful, therapeutic response in one group of patients. We are looking at why other patients don’t respond as well and the CIRM funding enables us to ask the questions that will, we hope, provide the answers.

Because our clinical trial is a being carried out at the CIRM-supported City of Hope Alpha Stem Cell Clinic this is a great example of how CIRM supports all the different ways of advancing therapy from early stage research through translation and into clinical trials in the CIRM Alpha Clinic network.

There are lots of ways the tumor tries to evade the immune system and we are looking at different approaches to combine this therapy with different approaches to see which combination will be best.

It’s a challenging problem and it’s not going to be solved with one approach. If it were easy we’d have solved it by now. That’s why I love science, it’s one big puzzle about how do we understand this and how do we make this work.

I don’t think we would be where we are at without CIRM’s support, it really gave the funding to bring this to the next level.”

Dr. Brown’s work is also creating interest among investors. She recently partnered with Mustang Bio in a $94.5 million agreement to help advance this therapy.