Since the discovery of insulin in 1922, no drug has been able to alter the course of Type 1 diabetes — until recently.

Now the medication teplizumab delays onset of the condition by an average of two years — and sometimes by more than a decade, says Kevan Herold, MD, a principal investigator of the drug and an immunologist at Yale Medicine in New Haven, Connecticut.

That’s a significant development given that 30,000 U.S. patients are diagnosed with the autoimmune condition each year.

In those individuals, the pancreas produces little or no insulin, the hormone responsible for controlling blood sugar levels. Potential long-term consequences include damage to the heart, kidneys, arteries, and eyes. And if blood sugar levels suddenly drop too low, patients can even fall into a coma.

“People with Type 1 diabetes are dependent on insulin every moment of every day,” says Herold. “Even a week without the disease is a gift.”

Unlike Type 2 diabetes, which can be forestalled with lifestyle changes, Type 1 diabetes previously had not responded to efforts to prevent or delay it.

Herold and other researchers focused on people with a high likelihood of developing the disease, hoping to help them before their immune system destroyed much of the pancreas. They worked with an international network of clinical trial sites, TrialNet, to search for individuals with at least two Type 1 biomarkers and abnormal blood sugar levels. Such individuals are believed to have a lifetime risk of developing the disease that’s close to 100%.