A new cancer immunotherapy is substantially enhanced by mRNA vaccine technology

A novel early-stage clinical trial focusing on an innovative cancer immunotherapy known as CAR-T cell therapy has shown promising signs for a potential cancer treatment that combines immunotherapy with an mRNA vaccine.

Based on the results of the Phase 1 human trial, the novel experimental treatment seems to be both safe and potentially effective in patients with solid tumors.

The findings of the study were presented at the American Association of Cancer Research (AACR) conference on Sunday, revealing that CAR T-cells may be able to reduce some solid tumors if given a boost from an mRNA vaccine.

What is CAR-T cell immunotherapy?

CAR-T (chimeric antigen receptor T-cell) treatment entails reprogramming the patient's own immune system cells to target and attack their cancer. Known to be a sophisticated and potentially risky treatment, it's tailored to each individual patient. It has been demonstrated in studies to cure some patients, proving itself to be a groundbreaking new treatment for blood cancers, even when other therapies have failed.

However, many studies have failed to get it to work safely in cancers featuring solid tumors. In fact, it has been difficult to develop strategies to get the modified T-cells to target solid tumor cells, according to John Haanen, an oncologist from the Netherlands Cancer Institute who is working on the new mRNA study.

The new study

The new therapy is delivered in two stages. First, a patient receives standard CAR-T cell treatment, in which the immune cells are designed to target an antigen known as claudin 6. (CLDN6).

According to New Atlas, previous research has suggested that CLDN6 is a suitable antigen target for solid tumors. That's because it is located on the surface of many types of cancer cells but not on the surface of healthy cells.

A few days after receiving the CAR-T cells, the patient is given an injection of an mRNA vaccine, which is intended to stimulate cell production of claudin 6. This additional antigen boost causes the modified T-cells to multiply, and more cancer-targeting T cells means a higher chance of those cells attacking and eliminating tumors.

Human trials

In the first human trial of the experimental treatment, there were 16 patients. The majority of the patients had either testicular or ovarian cancer.

The researchers reported that roughly 40 percent of the patients developed an inflammatory side effect known as cytokine release syndrome, which is a common side effect of CAR-T cell therapy. In the small trial, this excessive immune response was "manageable" and not severe in any patient.

In an interview with STATnews, Haanen stated that six of the 14 patients saw significant reductions in tumor size.

“I was quite skeptical at first because CAR T-therapy hadn’t worked before in solid tumors, so we were very excited to see how the metastases disappeared and the patients improved,” Haanen said. “These patients had a wonderful partial response, and one patient had a complete remission that is still ongoing, lasting now for almost six months.”

It should be noted that these are early Phase 1 results. Before it can be called a breakthrough, much more research is needed to determine the optimum approach to using this unique treatment.