AimsTo assess pharmacokinetics (PK) and safety of GP2015, a proposed etanercept biosimilar, in two studies: comparison with etanercept originator (ETN, bioequivalence study) and comparison of GP2015 administered via an autoinjector (AI) or prefilled syringes (PFS, delivery study). MethodsBoth studies were randomized, two-sequence, two-period, crossover studies conducted in healthy male subjects. In the bioequivalence study, subjects were randomized to receive a single 50mgsubcutaneous (s.c.) injection of GP2015 or ETN. In the delivery study, subjects were randomized to receive a single 50mgs.c. injection of GP2015 via AI or PFS. Following a wash-out period of 35days, subjects in the bioequivalence study received single 50mgs.c. injection of GP2015 or ETN, and subjects in the delivery study received single 50mgs.c. injection of GP2015 via AI or PFS. ResultsThe geometric mean ratios (90% confidence interval) of GP2015/ETN for C-max (1.11 [1.05-1.17]), AUC(0-tlast) (0.98 [0.94-1.02]) and AUC(0-inf) (0.96 [0.93-1.00]) were within the predefined bioequivalence range of 0.80-1.25. The geometric mean ratios (90% confidence interval) of AI/PFS for C-max (1.01 [0.94-1.08]), AUC(0-tlast) (1.01 [0.95-1.07]) and AUC(0-inf) (1.01 [0.96-1.07]) were also within the range 0.80-1.25. No new safety issues were reported. Three subjects had low titres of non-neutralising anti-drug antibodies during a follow-up visit in the bioequivalence study. ConclusionsThe PK of GP2015 was similar to ETN, demonstrating bioequivalence. The safety profile of GP2015 was consistent with previous reports for ETN. The GP2015 AI provided equivalent dosing and tolerability to the GP2015 PFS.