RESEARCH TRIANGLE PARK – A team of North Carolina scientists has developed an implantable scaffold resembling a “mini marshmallow” that produces and releases CAR-T cells for attacking cancerous tumors.

In a proof-of-concept study involving lymphoma in mice, researchers from North Carolina State University and the University of North Carolina at Chapel Hill found that treatment with the implant was faster and more effective than cancer therapy using conventional CAR-T cells.

If the technology eventually works in people as it did in the mice, it would likely be a much cheaper and quicker alternative to conventional CAR-T cancer therapy, the researchers said in a news release issued by NC State.

The research was supported in part by a $24,000 Flash grant to NC State awarded by the North Carolina Biotechnology Center in 2019, in addition to federal grants. Flash grants support the development of creative ideas that show early indications of commercial potential as life sciences technologies.

A bioinstructive scaffold (white) developed by the researchers, produces and releases genetically reprogrammed T cells that target and destroy a growing tumor. Credit: Ella Maru Studio.

“NCBiotech is excited to have supported the development of this potentially important and novel CAR-T technology from its earliest stages,” said Tracey du Laney, Ph.D., senior director of science and technology development for the nonprofit organization. “This line of research holds great promise to reduce the costs and technical challenges associated with CAR-T therapies.”

A paper describing the research, titled “Bioinstructive Implantable Scaffolds for Rapid In Vivo Manufacture and Release of CAR-T Cells,” was published in the peer-reviewed scientific journal Nature Biotechnology on March 24.

CAR-T therapy on the rise

CAR-T cell therapy has in recent years become a promising new way to treat various cancers by leveraging T cells, a type of white blood cell of the immune system that fights certain pathogens that invade the body. Since 2017, six CAR-T cell therapies have been approved by the U.S. Food and Drug Administration for the treatment of blood cancers, including lymphomas, multiple myeloma and some types of leukemia, according to the National Cancer Institute.

The technology involves collecting T cells from a patient and transporting them to a sterile manufacturing facility, where they are activated with antibodies over several days. Then the cells are reprogrammed to include the CAR (chimeric antigen receptor) gene for targeting cancer cells.

The modified CAR-T cells are stimulated to multiply before being returned to the hospital and infused into the patient’s bloodstream.

“A major drawback to CAR-T cell treatment is that it is tremendously expensive – hundreds of thousands of dollars per dose,” said Yevgeny Brudno, corresponding author of the study and assistant professor in the joint biomedical engineering department at NC State and UNC. “Due to its cost, many people are shut out from this treatment.”

Brudno said one reason for the high cost is that the manufacturing process is complex, time-consuming and tailored to each cancer patient individually.

“We wanted to address challenges in CAR-T treatment related to both manufacturing time and cost,” he said.

Reducing the manufacturing time, which can take several weeks, is even more critical for patients with rapidly progressing disease, said Pritha Agarwalla, lead author of the study and a postdoctoral researcher in the joint biomedical engineering department.

A ‘mini marshmallow’ to the rescue

To tackle this challenge, the researchers created a bio-device called Multifunctional Alginate Scaffolds for T cell Engineering and Release, or MASTER. The work was done in partnership with Gianpietro Dotti, professor in the department of microbiology and immunology and co-leader of the immunology program at the Lineberger Cancer Center at UNC; and Frances Ligler, a professor of biomedical engineering at Texas A&M University.

“Our MASTER technology takes the cumbersome and time-consuming activation, reprogramming and expansion steps and performs them inside the patient,” Agarwalla said. “This transforms the multi-week process into a single-day procedure.”

MASTER is a biocompatible, sponge-like material with the look and feel of a miniature marshmallow. To begin treatment, researchers isolate T cells from the patient and mix them with an engineered virus containing the CAR gene. Researchers pour this mixture on top of the MASTER, which absorbs it.

MASTER is decorated with the antibodies that activate the T cells, so the cell-activation process begins almost immediately. Meanwhile, MASTER is surgically implanted into the patient – or in the recent studies, a mouse.

As the implanted T cells continue to become activated, they begin responding to the engineered viruses, which reprogram them into CAR-T cells.

“The large pores and sponge-like nature of the MASTER material brings the virus and cells close together, which facilitates cellular genetic reprogramming,” Agarwalla said.

The MASTER material is also impregnated with protein factors called interleukins that foster cell proliferation. After implantation, these interleukins begin to leach out, promoting rapid proliferation of the CAR-T cells.

Successful in lymphoma studies

In the animal studies, the researchers worked with mice that had lymphoma. One group was treated with CAR-T cells that were created and delivered using MASTER. A second group was treated with CAR-T cells that were created conventionally and delivered intravenously. These two groups were compared to a control group receiving non-engineered T cells.

“Our technology performed very well,” Brudno said. “It would take at least two weeks to create CAR-T cells from naïve (non-activated) T cells for clinical use. We were able to introduce the MASTER into a mouse within hours of isolating naïve T cells.”

In addition, because cells are implanted within hours of isolation, the minimal manipulation creates healthier cells that exhibit fewer markers associated with poor anti-cancer performance in CAR-T cells. Specifically, the MASTER technique results in cells that are less differentiated, which translates to better sustainability in the body and more anti-cancer potency. In addition, the cells display fewer markers of T-cell exhaustion, which is defined by poor T cell function.

“The end result is that the mice that received CAR-T cell treatment via MASTER were far better at fighting off tumors than mice that received conventional CAR-T cell treatment,” Agarwalla said.

The improvement in anti-cancer efficacy was especially pronounced over the long term, when mice were faced with a recurrence of lymphoma.

Further potential for technology

“The MASTER technology was very promising in liquid tumors, such as lymphomas, but we are especially eager to see how MASTER performs against solid tumors, including pancreatic cancer and brain tumors,” Brudno said.

“We’re working with an industry partner to commercialize the technology, but there’s still a lot of work to be done before it becomes clinically available. Further work to establish the safety and robustness of this technology in animal models will be necessary before we can begin exploring clinical trials involving human patients.”

The researchers are also exploring opportunities with other industry partners for applying the fundamental concepts of MASTER in regenerative medicine and in treating autoimmune disease.

“I feel like we’re just scratching the surface of what’s possible here,” Agarwalla said.

(C) N.C. Biotech Center