Immunotherapy for type 1 diabetes shows promise in U.S. trial

A novel therapy that involves the use of patients' own immune cells, known as immunotherapy, has shown early promise in treating type 1 diabetes (T1D), U.S. researchers said Wednesday.

An early clinical trial showed that infusions of immune cells called regulatory T cells, or Tregs, are safe and can persist in T1D patients for at least one year, they reported in the U.S. journal Science Translational Medicine.

If the therapy does protect the body's ability to produce insulin in later trials, it "could be a game-changer," first author Jeffrey Bluestone, professor of the University of California, San Francisco, said in a statement.

"For type 1 diabetes, we've traditionally given immunosuppressive drugs, but this trial gives us a new way forward. By using Tregs to 're-educate' the immune system, we may be able to really change the course of this disease."

T1D is an autoimmune disease in which the immune system mistakenly destroys insulin-secreting beta cells in the pancreas. Many T1D therapies aim to tackle this problem by suppressing the immune response, but that approach can have serious consequences, including an increased susceptibility to infection or cancer.

According to the researchers, the new approach uses Tregs to dampen the immune system's assault on beta cells while leaving its infection-fighting capabilities intact.

In the completed Phase 1 trial, they first removed less than two cups of blood, which in T1D patients usually contained between 2 and 4 million of the desired Tregs, commingled with millions of cells of other types.

Using a method known as fluorescence-activated cell sorting, which precisely segregates cells based on molecules they display on their surface, they separated the therapeutic Tregs from the blood and then placed into a growth medium in which they can attain a 1,500-fold increase in number.

Bluestone and colleagues have shown in previous work that Tregs recovered after this expansion are more functionally active, can repair defects in the immune system of patients with T1D and are more likely to survive long-term in the body than Tregs produced by other means.

Fourteen patients aged 18 to 43 years old, all with recent-onset T1D, were organized into four groups that successively received infusions containing greater numbers of Tregs: members of the first group received about 5 million cells, and the fourth group about 2.6 billion cells.

In addition to being well tolerated by all four groups, the treatments were durable, with up to 25 percent of the infused therapeutic cells still detectable in patients' circulation a year after they had received just a single infusion.

The positive safety results from the trial are "particularly reassuring," because in some instances T cells that were therapeutically introduced in cancer treatment have caused patients' immune systems to spiral out of control, they said.

Based on the Phase 1 data from this trial, New Jersey-based Caladrius Pharmaceuticals is now in the early stages of planning a Phase 2 trial to test the effectiveness of the new therapy, according to the research team. Endit