Both agents are GLP-1 receptor agonists, but do they differ?
Highly similar efficacy and adverse event rates
Dulaglutide 1.5mg/week and liraglutide (Victoza) 1.8mg/day are comparable in important respects. At these doses, once-weekly dulaglutide is non-inferior (of equivalent potency) to once-daily liraglutide for least-squares mean reduction in HbA1c, with a similar safety and tolerability profile (AWARD-6).10
The AWARD-6 non-inferiority trial was performed in patients with type 2 diabetes using metformin with a baseline HbA1c level ≥53mmol/mol and ≤86mmol/mol. The mean reduction in HbA1c over 26 weeks with the additional use of dulaglutide and liraglutide was -1.42% and -1.36%, respectively [a non-inferiority margin for the study was 0.4%; mean treatment difference was -0.06% (95% confidence interval -0.19 to 0.07, p non-inferiority <0.0001)].10
The most common adverse events reported were gastrointestinal, with similar rates of study, or study drug, discontinuation because of adverse events between the two groups (6 per cent in each). No severe hypoglycaemia was reported in either group.10
Two further trials have focused on efficacy in terms of reduction in the primary combined endpoint of death from cardiovascular cause, non-fatal myocardial infarction, or non-fatal stroke in patients with type 2 diabetes with high CVD risk. The risk reduction [hazard ratio] in the primary endpoint attributable to standard care plus the study drug, versus standard care plus placebo, was 0.88 for dulaglutide 1.5mg/week (REWIND trial, median follow-up 5.4 years)11 and 0.87 for liraglutide 1.8mg/day (LEADER trial, follow-up 3.8 years).12
Differences in dosage, frequency and delivery
Where dulaglutide and liraglutide (Victoza) noticeably differ is in their dosage, frequency and the delivery device used. This is an area where prescribers and patients will need education and to be alert.
Dulaglutide 1.5mg is delivered once weekly using a single-use, subcutaneous autoinjector pen. The dose can be administered at any time of the day, with or without meals, and can be injected subcutaneously in the abdomen, thigh, or upper arm.6
Liraglutide (Victoza) is delivered once-daily, subcutaneously in the same sites as dulaglutide using a titratable-dose, multi-use, subcutaneous autoinjector pen. The Victoza pen contains 18mg liraglutide in 3ml solution, providing:
- 30 doses of 0.6mg or
- 15 doses of 1.2mg or
- 10 doses of 1.8mg.
Patients starting liraglutide are advised to begin with 0.6mg/day for one week to improve gastrointestinal tolerability, increasing to 1.2mg/day in week two if tolerated and, if the glycaemic response has not met target HbA1c, the prescriber may recommend an increase to 1.8mg/day. (The increase to 1.8mg can be within two or three weeks if measurements show blood glucose levels are still high and the drug is being tolerated.)5 Doses above 1.8mg/day are not recommended. The dose can be given at any time of day, with or without meals, but settling on a preferred regular time of day is advised.3
Switching from dulaglutide to liraglutide
If a patient should need to be switched from dulaglutide 1.5mg/week to liraglutide (Victoza), the same gradual dose escalation, starting at liraglutide 0.6mg/day, should be followed.5
Full product details and supportive evidence can be found in the respective data sheets for dulaglutide6 and liraglutide (Victoza).3
Health Navigator has produced patient resources for dulaglutide13 and liraglutide (Victoza)14 which give useful information for users of the medicines.