Dulaglutide

What it is

Dulaglutide (Trulicity) is a once-weekly GLP-1 receptor agonist developed by Eli Lilly and FDA-approved in 2014 for type 2 diabetes. The molecule is structurally distinct from other GLP-1 agonists — it consists of two GLP-1 analog moieties covalently linked to an immunoglobulin Fc fragment, creating a much larger molecule (about 60 kDa) than peptide-based GLP-1 agonists.

The Fc fusion construction provides extended half-life (~5 days) supporting once-weekly dosing while also potentially reducing immunogenicity compared to other peptide constructs. Dulaglutide is administered through a single-use, ready-to-use pen device.

Mechanism of action

The GLP-1 analog moieties bind GLP-1 receptors with effects identical to other GLP-1 receptor agonists: glucose-dependent insulin secretion, glucagon suppression, slowed gastric emptying, and central appetite effects. The Fc fusion does not change the fundamental pharmacology, only the pharmacokinetics.

Clinical use and evidence

The AWARD trial program established dulaglutide efficacy for type 2 diabetes:

• HbA1c reductions of approximately 1.5–1.6% across various comparator-controlled trials
• Weight loss of approximately 2–3 kg over 26–52 weeks (smaller than semaglutide or tirzepatide)
• REWIND cardiovascular outcomes trial: demonstrated cardiovascular benefit in patients with and without established cardiovascular disease — a finding that supported expanded label indications

Dulaglutide is FDA-approved for type 2 diabetes and cardiovascular risk reduction in adults with type 2 diabetes. It is not specifically approved for chronic weight management as a primary indication.

Why we don’t prescribe it routinely at The Tide

Dulaglutide produces meaningful glycemic improvements but smaller weight loss effects than semaglutide or tirzepatide. For our metabolic and weight management patient population, the larger effect sizes of semaglutide and tirzepatide are typically preferred. Dulaglutide remains a reasonable choice for type 2 diabetes management when prescribed by primary care or endocrinology, particularly for patients who tolerate it well or have specific reasons not to use newer agents.

Patients already established on dulaglutide who are achieving good results can continue with their prescribing physician. We do not typically initiate dulaglutide for new patients given the availability of more effective alternatives.

Side effects and contraindications

Side effect profile parallels other GLP-1 agonists, with GI effects during titration, pancreatitis risk, gallbladder events, and medullary thyroid cancer warning. Some patients experience injection site reactions specific to the Fc-containing molecule. Contraindicated in personal/family history of medullary thyroid cancer, MEN-2, pancreatitis history, and pregnancy.