Albiglutide, developed for treatment of type 2 diabetes mellitus, is provided in a dual-chamber cartridge (DCC) single-dose pen-injector containing lyophilized drug that must be reconstituted with diluent prior to use. A liquid formulation of albiglutide has been developed that does not require mixing. In this 2-period, randomized, crossover, double-blind, phase I study (NCT02660736) in 59 healthy volunteers, pharmacokinetic parameters were determined and the bioequivalence of the 2 formulations was assessed. Participants received injections from each type of pen-injector, one containing albiglutide 50 mg and one containing placebo, followed by an 8-week washout period between regimens: albiglutide 50-mg liquid formulation from an auto-injector and lyophilized placebo from a DCC pen-injector (Regimen A), or placebo liquid from an auto-injector and lyophilized albiglutide 50 mg from a DCC pen-injector (Regimen B). Geometric mean total exposures (area under the drug concentration–time curve [AUC](0-t) [1345.4 vs 1426.9 (μg · h/mL)], AUC(0-∞) [1376.2 vs 1454.6 (μg · h/mL)], and maximum concentration of drug in blood plasma [4968.5 vs 5314.7 ng/mL]) were comparable between Regimens A and B. Ratios of geometric least square means (90% confidence interval) were 95.3% (89.49–101.52) for AUC(0-∞), 95.1% (89.12–101.49) for AUC(0-t), and 93.2% (86.76–100.17) for maximum concentration of drug in blood plasma, falling within the 90% confidence interval of 0.80 to 1.25 for bioequivalence. No new safety concerns were observed.