A randomized phase l pharmacokinetic study comparing SB4 and etanercept reference product (Enbrel®) in healthy subjects.

AIMS: SB4 has been developed as a biosimilar of etanercept. The primary objective of the present study was to demonstrate the pharmacokinetic (PK) equivalence between SB4 and European Union -sourced etanercept (EU-ETN), SB4 and United States-sourced etanercept (US-ETN), and EU-ETN and US-ETN. The safety and immunogenicity were also compared between the treatments. METHODS: This was a single-blind, three-part, crossover study in 138 healthy male subjects. In each part, 46 subjects were randomized at a 1:1 ratio to receive a single 50 mg subcutaneous dose of the treatments (part A: SB4 or EU-ETN; part B: SB4 or US-ETN; and part C: EU-ETN or US-ETN) in period 1, followed by the crossover treatment in period 2 according to their assigned sequences. PK equivalence between the treatments was determined using the standard equivalence margin of 80-125%. RESULTS: The geometric least squares means ratios of AUCinf , AUClast and Cmax were 99.04%, 98.62% and 103.71% (part A: SB4 vs. EU-ETN); 101.09%, 100.96% and 104.36% (part B: SB4 vs. US-ETN); and 100.51%, 101.27% and 103.29% (part C: EU-ETN vs. US-ETN), respectively, and the corresponding 90% confidence intervals were completely contained within the limits of 80-125 %. The incidence of treatment-emergent adverse events was comparable, and the incidence of the antidrug antibodies was lower in SB4 compared with the reference products. CONCLUSIONS: The present study demonstrated PK equivalence between SB4 and EU-ETN, SB4 and US-ETN, and EU-ETN and US-ETN in healthy male subjects. SB4 was well tolerated, with a lower immunogenicity profile and similar safety profile compared with those of the reference products.