Dulaglutide: Research Overview

Dulaglutide, marketed as Trulicity by Eli Lilly and Company, is a once-weekly injectable glucagon-like peptide-1 (GLP-1) receptor agonist approved by the FDA for glycaemic control in type 2 diabetes and, following the REWIND cardiovascular outcomes trial, for reduction of major adverse cardiovascular events (MACE) in adults with type 2 diabetes with established cardiovascular disease or multiple cardiovascular risk factors. Its large evidence base, built through the AWARD clinical trial program and the REWIND outcomes study, makes it one of the most thoroughly characterised GLP-1 receptor agonists in clinical medicine.

What is Dulaglutide?

Dulaglutide is a fusion protein consisting of two GLP-1(7-37) analogue peptides covalently linked to a modified human immunoglobulin G4 (IgG4) Fc region. This large-molecule design prolongs half-life to approximately 4.7 days, enabling once-weekly subcutaneous dosing. It received initial FDA approval in September 2014 for improvement of glycaemic control as an adjunct to diet and exercise in adults with type 2 diabetes. In June 2020, the FDA approved the expanded cardiovascular risk reduction indication based on REWIND trial data.

Approved doses are 0.75 mg, 1.5 mg, 3.0 mg, and 4.5 mg administered subcutaneously once weekly. The higher doses (3.0 mg and 4.5 mg) were evaluated in the AWARD-11 trial and approved by the FDA in 2020 for additional glycaemic lowering in patients who needed more intensive control.

Mechanism of Action

Dulaglutide binds the GLP-1 receptor (GLP-1R), a Gs-protein-coupled receptor expressed on pancreatic beta cells, the gastrointestinal tract, the heart, and the central nervous system. On pancreatic beta cells, GLP-1R activation stimulates glucose-dependent insulin secretion: insulin release is amplified when blood glucose is elevated, but the mechanism is largely glucose-dependent, substantially reducing the risk of hypoglycaemia compared with sulphonylureas or insulin.

Additional pharmacodynamic effects include suppression of glucagon secretion (reducing hepatic glucose output), slowing of gastric emptying (contributing to postprandial glucose control and appetite suppression), and central satiety signalling via hypothalamic GLP-1 receptors. These combined effects result in reduced HbA1c, modest body weight reduction, and potentially reduced cardiovascular events through mechanisms that are still being elucidated — candidates include anti-inflammatory effects on coronary vasculature, reduced plaque progression, and haemodynamic benefits.

What the Research Shows

The AWARD program comprised at least 11 phase 3 randomised controlled trials evaluating dulaglutide across a spectrum of type 2 diabetes backgrounds — drug-naive patients, metformin-treated patients, patients on basal insulin, and patients with renal impairment. Across these trials, dulaglutide 1.5 mg consistently achieved HbA1c reductions of approximately 1.0–1.6% from baseline, with superiority to active comparators including sitagliptin, exenatide, and glargine in several studies, and non-inferiority to liraglutide 1.2 mg in AWARD-6 (PMID 25018121). A comprehensive review of AWARD data (PMID 27102969) confirmed a favourable efficacy and tolerability profile across the program.

The landmark REWIND trial (Gerstein et al., The Lancet, 2019; PMID 31189511) enrolled 9,901 adults with type 2 diabetes across 371 sites in 24 countries. The mean age was 66.2 years, median HbA1c was 7.2%, and 46% of participants were women — notably more diverse than many predecessor CVOT trials. Participants had either established cardiovascular disease or multiple CV risk factors. Over a median follow-up of 5.4 years, the primary composite endpoint (non-fatal myocardial infarction, non-fatal stroke, or CV death) occurred in 12.0% of the dulaglutide group versus 13.4% of the placebo group (HR 0.88, 95% CI 0.79–0.99; p=0.026). This was a 12% relative risk reduction in MACE.

All-cause mortality did not differ significantly (HR 0.90, 95% CI 0.80–1.01; p=0.067). The REWIND results were notable for including a substantial proportion of participants without prior CV events (primary prevention context), suggesting potential broader applicability than earlier GLP-1 CVOT results that were enriched for high-risk patients.

The AWARD-11 trial (PMID 33397768) evaluated higher doses (3.0 mg and 4.5 mg) versus the standard 1.5 mg and demonstrated dose-dependent HbA1c reductions (an additional 0.5–0.6% from the 1.5 mg baseline) and further weight reductions of approximately 1–2 kg, supporting the expanded dose range approved in 2020.

Pharmacokinetics

Dulaglutide has a mean elimination half-life of approximately 4.7 days after subcutaneous injection, consistent with its IgG4 Fc fusion design that retards renal clearance and proteolytic degradation. Steady-state concentrations are reached after approximately 2–4 weeks of once-weekly dosing. Peak plasma concentrations (Tmax) occur 24–72 hours post-injection. Subcutaneous bioavailability is approximately 65–70%. Unlike small-molecule GLP-1 receptor agonists, dulaglutide is cleared primarily by proteolytic catabolism into peptide fragments and amino acids, without significant renal excretion of intact drug, which allows use across the spectrum of renal function without dose adjustment.

Common Research Dose Ranges

Not medical advice. These are ranges reported in research literature, not personalized recommendations. Consult your physician.

Dulaglutide is an approved pharmaceutical with established dosing from clinical trials. The AWARD program used 0.75 mg and 1.5 mg once-weekly doses as the primary dose range. The AWARD-11 trial added 3.0 mg and 4.5 mg doses. In approved clinical practice, treatment is typically initiated at 0.75 mg once weekly and may be escalated to 1.5 mg based on glycaemic response. Further escalation to 3.0 mg or 4.5 mg is possible per prescribing information.

Storage and Handling

Trulicity is supplied as a single-dose pen injector containing 0.5 mL solution. Per the approved label, it should be stored refrigerated at 2–8°C (36–46°F). It may be stored at room temperature (below 30°C / 86°F) for up to 14 days. Pens should not be frozen; frozen product should be discarded. Protect from light and heat. Do not use if the solution is cloudy, coloured, or contains particles.

What It Is NOT

Dulaglutide is not insulin and does not replace insulin in type 1 diabetes or in type 2 diabetes where insulin is required. It is not semaglutide (Ozempic/Wegovy), liraglutide (Victoza/Saxenda), or tirzepatide (Mounjaro/Zepbound) — each is a distinct molecule with different receptor binding, half-life, and regulatory approvals. Dulaglutide does not carry an FDA-approved indication for chronic weight management (unlike semaglutide 2.4 mg or tirzepatide) — weight loss is a secondary effect observed in trials, not the primary approved indication. It is also not approved for type 1 diabetes, gestational diabetes, or use in children below the approved age range.

References

Key citations include the REWIND trial primary publication (PMID 31189511, The Lancet 2019), the AWARD program comprehensive review (PMID 27102969), AWARD-6 (PMID 25018121), AWARD-11 (PMID 33397768), and the FDA Trulicity prescribing information.