Researchers have found that a cheap and widely available tuberculosis vaccine can bring blood sugar levels almost back to normal in patients with type 1 diabetes. The century-old bacillus Calmette-Guérin (BCG) vaccine is affordable and accessible, and if the results of the study hold up, it could be a game-changing development in the treatment of diabetes.
According to the paper’s senior author, Massachusetts General Hospital Immunobiology Laboratory director, Dr. Denise Faustman:
“Obviously it’s going to be jarring to some people. The last 15 years there’s been billions of dollars of immunotherapy in trials. Along we come with something that was before everyone’s eyes for 100 years. And it appears to be filling a clinical gap that has not been filled with insulin.”
The study was small, but eight years later, the blood sugar of diabetics who received the vaccine was much better controlled than those who had not.
Earlier animal testing had suggested that the vaccine, used to prevent tuberculosis and certain forms of bladder cancer, could combat the immune system errors that cause type-1 diabetes. The disease arises when the immune system destroys the cells in the body that create insulin.
Faustman’s team tracked 282 people, including 52 diabetics who received the vaccine. Three years afterwards, six of the diabetics had blood sugar levels near normal, and lower levels than those who had been given a placebo.
“We still have to use insulin, but we’re finally able to get to the nearly normal range. Nobody’s been able to do that before,” she explained.
It took two doses, a month apart, and a three-year wait for the benefits to be seen, after which no extra treatment was needed.
The team expected the vaccine to accomplish this by helping to regenerate pancreatic cells. Instead, they found that it alters the way the body metabolizes sugar.
Managing the disease with insulin can be an expensive and difficult process. Patients wear an insulin pump and a glucose monitor. Too much insulin can be deadly. Faustman explains:
“Insulin is not a smart drug. Once you give someone more and more insulin it just keeps lowering blood sugar, and you could die.”
And the cost of insulin has soared in recent years, even though it is a 100-year old drug. Diabetes cost $327 billion in the US in 2017, up from $245 billion in 2012.
Much more research will be needed before the new findings can lead to new options to treat diabetes. According to the director of the Brigham and Women’s Diabetes Program, Dr. Mary McDonnell:
“This is very preliminary, and that’s important. But on a positive note, this kind of work should be encouraged and has to be certainly explained in clear terms to the community, so patients with type 1 diabetes and families have the appropriate amount of hope.”