On November 17, 2022, the U.S. Food and Drug Administration (FDA) approved the first drug that can delay the onset of type 1 diabetes . Tzield (teplizumab-mzwv) is approved for use in adults and children over 8 years with stage 2 (presymptomatic) type 1 diabetes to delay the progression to stage 3 (symptomatic) type 1 diabetes. Type 1 diabetes occurs when a person’s immune system attacks and destroys beta-cells in their pancreas. These beta-cells produce insulin in the body, which regulates blood glucose levels. Without insulin-producing beta-cells, patients experience high blood glucose levels and need to receive insulin injections or wear insulin pumps to control their glucose. These treatments are costly and are necessary for a patient’s survival. Tzield works by binding to and deactivating the immune cells that destroy pancreatic insulin-producing cells, thereby delaying progression to symptomatic disease and the burdens of its treatment. Tzield was shown to be safe and effective in a clinical trial that evaluated 76 patients with stage 2 type 1 diabetes. The patients received a once-daily intravenous infusion for 14 days of either Tzield or a placebo. After 51 months (about 4 and a half years), 45% of the patients receiving Tzield and 72% of the patients receiving placebo were diagnosed with stage 3 type 1 diabetes, showing that Tzield prevented progression better than placebo. The most common side effects reported with Tzield were rash, headache and decreased white blood cell count. Patients receiving Tzield should be monitored for decreased white blood cell counts, hypersensitivity reactions and an overreaction of the immune system in response to the injection known as Cytokine Release Syndrome. For the first 5 days of treatment, patients should be premedicated with a nonsteroidal anti-inflammatory drug or acetaminophen, an antihistamine and/or a medication to prevent nausea and vomiting before giving the infusion. Prior to starting Tzield, patients should be up to date on their age-appropriate vaccinations, and they should avoid use of live, inactivated and mRNA vaccines during use.