FDA Approves New Treatment for T2D

The US Food and Drug Administration (FDA) has approved a novel, first-in-class treatment option, tirzepatide (Mounjaro), for the treatment of type 2 diabetes in adults. This treatment option was more effective at improving blood sugar than other treatment options that were evaluated.

Tirzepatide works by targeting both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors.

The approval was based on the results of 5 clinical trials that evaluated the efficacy of tirzepatide as both a stand-alone therapy and as an add-on therapy to other treatment options. Researchers examined 3 doses of tirzepatide: 5 mg, 10 mg, and 15 mg. Tirzepatide was compared with placebo, a GLP-1 receptor agonist (semaglutide), and 2 long-acting insulin analogs.

The results indicated that 15 mg of tirzepatide as a stand-alone therapy lowered hemoglobal A1c levels (HbA1c) by more than 1.6% on average when compared with placebo, and 1.5% more on average when used in addition to a long-acting insulin. Patients who were randomized to receive tirzepatide lowered their HbA1c by 0.5% more than semaglutide, 0.9% more than insulin degludec, and 1.0% more than insulin glargine.

Additionally, patients who received 15 mg of tirzepatide had an average weight loss that was 15 pounds more than the placebo group when not used with insulin, and 23 pounds more when used with insulin. This weight loss in the tirzepatide  group was 12 pounds more than semaglutide, 29 pounds more than insulin gludec, and 27 pounds more than insulin glargine. However, weight gain was common among individuals receiving insulin without tirzepatide.

The treatment is to be administered as a once weekly subcutaneous injection. Potential adverse effects include nausea, vomiting, diarrhea, decreased appetite, constipation, upper abdominal discomfort and abdominal pain.

Tirzepatide is not indicated for use in individuals with type 1 diabetes and has not been studied in patients with a history of pancreatitis. The treatment was observed to cause thyroid C-cell tumors in rats, but the relationship is currently unknown in humans. Tirzepatide should not be used in individuals with a history of medullary thyroid cancer, or Multiple Endocrine Neoplasia syndrome type 2.


—Leigh Precopio



FDA approves novel, dual-targeted treatment for type 2 diabetes. News release. US Food and Drug Administration; May 13, 2022. Accessed May 16, 2022.

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