FDA OKs Tirzepatide Injection for T2D

The FDA approved a novel dual-targeted treatment, injectable tirzepatide, alongside diet and exercise, to help achieve blood sugar control in adult patients with type 2 diabetes (T2D).

Tirzepatide is the first in a new drug class called dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists. As the name suggests, the drug is capable of activating both the GLP-1 and GIP receptors to improve blood sugar control—an "important advance" in treating patients with T2D, given "the challenges many patients experience in achieving their target blood sugar goals," said Patrick Archdeacon, MD, associate director of the Division of Diabetes, Lipid Disorders, and Obesity in the FDA’s Center for Drug Evaluation and Research, in a statement.

Tirzepatide was assessed at three different doses—5 mg, 10 mg, and 15 mg—across five clinical trials, acting as both stand-alone and add-on therapy. In these trials, the drug was pitted against placebo, semaglutide, and a pair of long-acting insulin analogs, the FDA explained.

"On average, patients randomized to receive the maximum recommended dose of [tirzepatide] (15 milligrams) had lowering of their hemoglobin A1c (HbA1c) level… by 1.6% more than placebo when used as stand-alone therapy, and 1.5% more than placebo when used in combination with a long-acting insulin. In trials comparing [tirzepatide] to other diabetes medications, patients who received the maximum recommended dose of [tirzepatide] had lowering of their HbA1c by 0.5% more than semaglutide, 0.9% more than insulin degludec and 1.0% more than insulin glargine."

The agency also noted that obesity was common among study participants, and patients randomized to the maximum recommended tirzepatide dose saw improved weight loss, as follows:

• Lost an additional 15 pounds and 23 pounds versus placebo when used without and with insulin, respectively.
• Lost an additional 12 pounds versus semaglutide, 29 pounds versus degludec, and 27 pounds versus insulin glargine.

The most common side effects seen with tirzepatide included nausea, vomiting, diarrhea, decreased appetite, constipation, upper abdominal discomfort, and abdominal pain. Also, the drug was shown to cause thyroid C-cell tumors when administered to rats; while it is unknown whether the drug causes these tumors in humans, the FDA warned that it should not be used in patients with a personal or family history of medullary thyroid cancer or in patients with Multiple Endocrine Neoplasia syndrome type 2.

The drug also has not been studied in patients with a history of pancreatitis, and it is not indicated for use in patients with type 1 diabetes.

Injectable tirzepatide is marketed as Mounjaro by Eli Lilly and Co.