Immunotherapy is generally known as a treatment for cancer. In CAR T cell therapy, a patient's T cells can be isolated from blood samples, then genetically modified in the lab so those cells will express certain proteins on their surface. That modification is intended to make the T cells better at targeting antigens expressed on cancer cells, and eliminating those cells. Once modified, the T cells are returned to the patient so they can do their work. But now researchers have used modified T cells in a different way, to target B cells that can cause lupus.
Lupus is an autoimmune condition that can cause inflammation in various organs. The disorder can present in very different ways in different patients, although many patients have a skin rash, joint pain, and kidney problems. It's estimated that about 5 million people around the world have some form of lupus; the most common type is known as systemic lupus erythematosus (SLE).
In a clinical trial, four women and one man with SLE were treated with modified CAR T cells. In this trial, the CAR T cells were made to express a protein targeting CD19, an antigen on B cells. The treatment was successful in all of the patients, who had been experiencing severe complications in various organ systems because of their disease. The patients were able to stop taking other medications they'd been using to treat SLE, and the organ dysfunction resolved or improved. The findings from the trial were reported in Nature Medicine.
The researchers cautioned that more studies will be necessary to ensure that this treatment approach is safe and effective for other people with lupus, but the results are promising.
CAR T cell therapy can cause the release of a massive amount of inflammatory molecules called cytokines. While that shows that the CAR T cells are working, it can also be a serious complication of the treatment and is most often seen in people with extensive cancer growth. In this trial, only mild instances of cytokine-release syndrome were observed.
This CD19 CAR T cell therapy could be a very effective way to treat SLE patients. Unfortunately, CAR T cell therapy can be expensive, because it requires the extraction of patient cells, which then have to be modified so they can be safely returned to the patient; not every healthcare facility has the capabilities to prepare the treatment. However, it may still be less expensive than trying to develop new drugs.
A recent trial with one individual, which was reported in the New England Journal of Medicine, also showed that CAR T cell therapy can send lupus patients into long-term remission, in which they do not need drug treatments for their disease. However, more time will be needed to determine whether this approach is curative.