Phase I, randomized, double-blind, single-dose study to assess the pharmacokinetics, safety, and immunogenicity of the proposed biosimilar SCT630 and adalimumab in healthy Chinese subjects

We aimed to compare the pharmacokinetics, safety, and immunogenicity of the adalimumab biosimilar SCT630 with those of its reference (adalimumab, Humira®). This study involved a randomized, double-blind, parallel-controlled design; healthy subjects (N = 146) were randomly distributed into two groups to receive a single-dose subcutaneous injection of 40 mg SCT630 or 40 mg adalimumab, with a 71-day follow up. The bioequivalence of the primary pharmacokinetic parameters (AUC0-t) and maximum observed serum concentration (Cmax) between SCT630 and adalimumab were the primary endpoints; safety and immunogenicity of SCT630 compared with those of adalimumab were the secondary endpoints. The geometric mean Cmax ratio of SCT630 to adalimumab and its 90% confidence interval (CI) were 116.02% and 108.66%-123.88%, AUC0-t ratio and 90% CI were 109.47% and 99.80%-120.08%, and AUC0-∞ ratio and 90% CI were 109.24% and 99.80%-120.78%. These PK parameters fulfilled the equivalence criterion of 80.00%-125.00%. Treatment-emergent adverse events (TEAEs) occurred in 62 (84.9%) and 61 (83.6%) subjects; mild and moderate drug-related TEAEs were observed in 60 (82.2%) and 59 (80.8%) subjects in the adalimumab and SCT630 groups, respectively. On day 71, 69 (95.8%) subjects in the adalimumab group and 66 (93%) in the SCT630 group reported positive anti-drug antibodies. Among them, 15 (21.7%) and 11 (16.7%) subjects showed positive neutralizing antibodies, with no significant difference. SCT630 was well tolerated and demonstrated PK and safety profiles similar to adalimumab. The profiles support the initiation of further confirmatory study to demonstrate the clinical similarity of SCT630 to adalimumab.