Today, the U.S. Food and Drug Administration approved the Tzield (teplizumab-mzwv) injection to delay the onset of stage 3 type 1 diabetes in adults and pediatric patients 8 years and older who currently have stage 2 Type 1 diabetes. This is the first treatment approved to delay the onset of the symptomatic stage of Type 1 diabetes. 

“Today’s approval of a first-in-class therapy adds an important new treatment option for certain at-risk patients,” John Sharretts, director of the Division of Diabetes, Lipid Disorders, and Obesity in the FDA’s Center for Drug Evaluation and Research said in a statement. “The drug’s potential to delay clinical diagnosis of Type 1 diabetes may provide patients with months to years without the burdens of disease.” 

Type 1 diabetes is a disease that occurs when the immune system attacks and destroys the cells that make insulin. People with Type 1 diabetes diagnosis have increased glucose that requires insulin shots (or wearing an insulin pump) to survive and must check their blood sugar levels regularly throughout the day. Insulin shots begin as soon as possible after diagnosis, but symptoms often don’t appear until stage 3. 

 Although the disease can appear at any age, Type 1 diabetes is usually diagnosed in children and young adults. A person is at higher risk for Type 1 diabetes if they have a parent, brother or sister with Type 1 diabetes, although most patients with Type 1 diabetes do not have a family history.

[Related: Why we should be looking out for diabetes in young people with COVID.]

Stage 1 of Type 1 diabetes occurs when patients test for two or more diabetes-related autoantibodies but blood sugar levels remain normal. Once blood sugar levels become abnormal, a patient phases into stage 2, but there are often still no symptoms. However, stage 3 is the start of the “clinical diagnosis,” where symptoms like increased thirst and urination, weight loss, blurred vision, and fatigue set in. In some cases, patients in this stage are hospitalized with diabetic ketoacidosis which is potentially life threatening.

Tzield slows development of stage 3 by binding to certain immune system cells. The injection may deactivate the immune cells that attack insulin-producing cells, while increasing the proportion of cells that help moderate the immune response. Tzield is administered by intravenous infusion once daily for 14 consecutive days. 

Tzield’s safety and efficacy were evaluated in a randomized, double-blind, event-driven, placebo-controlled trial with 76 patients with stage 2 Type 1 diabetes. In the trial, patients randomly received Tzield or a placebo once daily via intravenous infusion for 14 days. The primary measure of efficacy was the time from randomization to development of stage 3 Type 1 diabetes diagnosis. Doctors followed up with patients on average 51 months after the Tzield shots. Forty-five percent of the 44 patients who received Tzield were later diagnosed with stage 3 Type 1 diabetes, compared to 72 percent of the 32 patients who received a placebo. 

The mid-range time from randomization to stage 3 Type 1 diabetes diagnosis was 50 months for the patients who received Tzield and 25 months for those who received a placebo. This represents a statistically significant delay in the development of stage 3 Type 1 diabetes. 

The most common side effects of Tzield include decreased levels of certain white blood cells (which can lead to increase risk of infections), rashes, and headaches. The use of Tzield comes with warnings and precautions, including guidelines to premedicate and monitor for symptoms of Cytokine Release Syndrome, a series of symptoms associated with T cell immunotherapy. 

Additionally, Tzied comes with a risk of serious infections, decreased levels of a type of white blood cell called lymphocytes, and risk of hypersensitivity reactions. Patients would need to receive all age-appropriate vaccinations prior to starting Tzield and avoid the concurrent use of live, inactivated, and mRNA vaccines with Tzield. 

Tzield received Priority Review and Breakthrough Therapy designations for this indication.