A recent phase 1 clinical trial suggests that CAR T-cell therapy could eventually offer a new treatment approach for people with severe rheumatoid arthritis (RA) that has not improved enough with other treatments. In the study, six people with severe RA received a single infusion of their own specially modified immune cells. All six had some improvement in their disease, and three reached a level of improvement that researchers classified as remission.

The treatment works differently from most RA medications. Instead of taking a medication regularly to control inflammation, CAR T-cell therapy uses specially modified immune cells to remove certain B cells, which are immune cells that can contribute to the autoimmune response involved in RA. The study also found decreases in antibodies associated with RA.

These results are encouraging, but they are very early. Only six people took part in the study, and there was no comparison group. Larger studies are needed before doctors will know how well it works, how long the benefits last, and which patients might benefit.

What Did the Recent CAR T-Cell Trial Test?

The study tested a CAR T-cell treatment called mivocabtagene autoleucel, or miv-cel, in six people with severe RA that had not improved enough with several previous treatments. All of the participants had a type of RA associated with certain antibodies called ACPA, which are found in many people with RA.

CAR T-cell therapy starts by collecting some of a patient’s own T cells, which are an important part of the immune system. Researchers then change these cells in a laboratory so they can recognize and attack a specific type of immune cell.

In this study, the modified T cells were designed to target B cells. B cells normally help protect the body from infections, but they can also play a role in autoimmune diseases such as RA. Once the T cells are modified, they are infused back into the patient.

Before receiving the treatment, participants received medication to temporarily reduce some of their existing immune cells. They then received one infusion of the modified T cells and were monitored for up to about a year.

Because this was a phase 1 trial, one of the main goals was to find out whether the treatment appeared safe. Researchers also looked at whether participants’ RA symptoms and blood tests improved.

What Were the Results of the RA CAR T-Cell Trial?

The results were promising, especially because the people in the study had severe RA that had not responded well to previous treatments.

All six participants had lower levels of RA disease activity after receiving the CAR T-cell treatment. Three of the six reached remission according to one standard measure used by researchers. The study also found that several participants had large reductions in RA-related antibodies in their blood.

Researchers believe these changes may be related to the treatment’s effect on B cells. The CAR T cells removed many of the targeted B cells from the blood and tissues. Over time, some of the antibodies associated with RA also decreased.

The treatment did cause side effects. All six participants developed a mild form of a reaction called cytokine release syndrome. This happens when the immune system becomes highly activated after CAR T-cell treatment. None of the participants developed a serious neurological complication known as ICANS, but one person had a temporary increase in liver enzymes. While serious, this side effect resolved.

It is important to put these results in perspective. Six patients is a very small number, so researchers cannot yet know whether similar results would occur in hundreds of people with RA.

How Is CAR T-Cell Therapy Different From Existing RA Treatments?

CAR T-cell therapy takes a different approach from most RA treatments currently used by rheumatologists.

Today, RA can be treated with several types of disease-modifying medications. These include methotrexate, biologic medications, and targeted medications such as JAK inhibitors. Different drugs work on different parts of the immune system to reduce inflammation and prevent joint damage.

Most of these treatments need to be taken regularly. The goal is to keep RA under control over the long term and prevent symptoms and joint damage from returning.

Rather than continuously taking a medication that blocks a particular part of the immune response, CAR T-cell treatment changes the patient’s own T cells so they can seek out and remove certain B cells. The hope is that this could interrupt the autoimmune process more deeply and potentially provide a longer period of disease control after a single treatment.

Why This Research Is Interesting

What makes this study particularly interesting is that researchers are trying to address RA at a different level than we usually do with medication.

Most RA treatments work by turning down parts of the immune system that are causing inflammation. CAR T-cell therapy takes a more targeted approach by changing a person’s own immune cells so they can remove certain B cells.

That does not mean we have found a cure for RA. The study involved only six people, and we do not yet know how long their improvements will last. CAR T-cell therapy also comes with risks and is a much more involved treatment than most RA medications.

For patients, this is an exciting area of research, but it won’t be replacing current RA treatments in the near future.

FAQs

What did the recent clinical trial actually test?

The trial tested a CAR T-cell treatment in six people with severe RA who had not gotten enough improvement from several previous treatments. Doctors collected each person’s T cells, modified them to recognize and eliminate problematic B cells, and gave the modified cells back through an infusion. The researchers then monitored the participants for signs of side effects and changes in their RA. All six had improvements in disease activity during the study.

Who might eventually benefit most from this therapy?

If future research confirms these findings, CAR T-cell therapy may be most useful for people with severe RA who have not responded well enough to several existing treatments. The first study focused on people with particularly difficult-to-control RA. It is too early to know whether the treatment could eventually be offered to people with milder RA or those who are doing well on their current medications.

Is CAR T-cell therapy available for people with rheumatoid arthritis now?

No. CAR T-cell therapy is still being studied as a treatment for RA. The recent study was very small and was designed primarily to look at safety and see whether the treatment showed enough promise to justify more research. Larger studies are needed before doctors can determine whether CAR T-cell therapy should become part of standard RA treatment.

Could CAR T-cell therapy cure rheumatoid arthritis?

It is too early to say whether CAR T-cell therapy could cure RA. Some people in the study reached remission, but the study was too small to determine whether the disease would stay away over the long term. Researchers will need to follow more patients for longer periods to understand whether CAR T-cell therapy can produce lasting remission or whether RA eventually returns.

Should I stop my RA medication because of this research?

No. The study does not show that people with RA should stop their current medications. Established RA treatments remain the best approach for controlling inflammation and preventing joint damage. If your current treatment is not working well, talk with your rheumatologist about your options rather than stopping medication on your own.