Cardiovascular safety of albiglutide in the Harmony programme: a meta-analysis

Background Albiglutide is a glucagon-like peptide-1 receptor agonist, a new class of drugs used to treat type 2 diabetes. We did a prospective meta-analysis of the cardiovascular safety of albiglutide as stipulated by the US Food and Drug Administration recommendations for the assessment of new treatments for diabetes. Methods We did a meta-analysis of eight phase 3 trials and one phase 2b trial in which patients were randomly assigned to albiglutide, placebo, or active comparators (glimepiride, insulin glargine, insulin lispro, liraglutide, pioglitazone, or sitagliptin). The safety population included 5107 patients, of whom 2524 took albiglutide (4870 person-years) and 2583 took comparators (5213 person-years). Possible major cardiovascular events were recorded prospectively and adjudicated by an independent endpoint committee masked to treatment allocation. The primary endpoint was a composite of first occurrence of major adverse cardiovascular events (ie, cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke) or hospital admission for unstable angina. Secondary endpoints were major adverse cardiovascular events alone, all-cause mortality, silent myocardial infarction, hospital admission for heart failure, chest pain, other angina, and subdural or extradural haemorrhage. The occurrence of all other adverse events classified by the investigators as cardiovascular events were documented, but these were not adjudicated. Findings The primary endpoint was not significantly different between albiglutide and all comparators (58 events vs 58 events; hazard ratio [HR] 1.00, 95% CI 0.68-1.49, p=0.0019 for non-inferiority). Major adverse cardiovascular event alone was also not significantly different (52 events vs 53; HR, 0.99; 95% CI, 0.65-1.49). When albiglutide was compared separately with placebo or active comparators, we noted no significant differences. We detected no significant differences in the other secondary endpoints. More patients had atrial fibrillation or atrial flutter in the albiglutide group (35 [1.4%] of 2524 patients; 8.6 events per 1000 patient-years) than in the all-comparators group (16 [0.6%] of 2583 patients; 3.4 events per 1000 patient-years). Interpretation Cardiovascular events were not significantly more likely to occur with albiglutide than with all comparators. Because the upper bound of the 95% CI for major adverse cardiovascular event plus hospital admission for unstable angina was greater than 1.3, a dedicated study with a cardiovascular endpoint is underway to confirm the safety of albiglutide.