POS0641 A RANDOMISED PHASE I PHARMACOKINETIC STUDY COMPARING HIGH-CONCENTRATION, LOW-VOLUME, AND CITRATE-FREE SB5 (40 MG/0.4 ML) WITH PRIOR SB5 FORMULATION, AND ADALIMUMAB BIOSIMILAR, IN HEALTHY MALE SUBJECTS

Abstract

BackgroundSB5, an adalimumab (ADL) biosimilar, was developed in a low-concentration (40 mg/0.8 mL, SB5-LC) aligned with the reference ADL product. Pharmacokinetics (PK) equivalence of SB5 and reference ADL was demonstrated in a Phase I study conducted in healthy subjects1. Equivalent efficacy and comparable safety between 40 mg/0.8 mL SB5 and 40 mg/0.8 mL reference ADL were demonstrated in a Phase III study conducted in patients with rheumatoid arthritis2. High-concentration, low-volume, citrate-free SB5 (40 mg/0.4 mL, SB5-HC) has been developed as a part of life cycle management in line with the reference ADL formulation.ObjectivesTo compare the PK, safety, and tolerability of the newly developed SB5-HC (40 mg/0.4 mL) to prior SB5-LC (40 mg/0.8 mL) in healthy male subjects.MethodsThis study was a randomised, single-blind, two-arm, parallel group, single-dose study in healthy male subjects. Subjects were randomised in a ratio of 1:1 to receive a single dose of either SB5-HC or SB5-LC by subcutaneous injection on Day 1 and then observed for 57 days during which the PK, safety, and immunogenicity were evaluated. The serum concentration of ADL was measured using an enzyme-linked immunosorbent assay. The primary PK parameters were area under the concentration-time curve from time zero to infinity (AUCinf) and maximum serum concentration (Cmax). Equivalence for the primary PK parameters was to be concluded if the 90% confidence intervals (CIs) for the ratio of geometric least squares means (LSMeans) of the treatment groups compared were completely contained within the pre-defined equivalence margin of 0.80 to 1.25 using an analysis of variance.ResultsOf 188 randomised subjects, 187 subjects were analysed as PK Analysis Set (PKS) (n=93 in SB5-HC and n=94 in SB5-LC). One subject was excluded from the PKS in SB5-HC group (major protocol deviation for not being withdrawn in the event of confirmed COVID-19). The geometric LSMeans ratios for the comparison of SB5-HC and SB5-LC for AUCinf and Cmax were 0.920 and 0.984, respectively, and the corresponding 90% CIs were within the pre-defined equivalence margin of 0.80 to 1.25 (Table 1), indicating the two treatment groups are bioequivalent. There were no deaths, serious adverse events or discontinuation of the study due to treatment-emergent adverse events (TEAEs) during the study. The proportions of subjects who experienced TEAEs were comparable between the two treatment groups (44.7% in SB5-HC vs 51.1% in SB5-LC). The most frequent TEAEs were headache (10.6% in SB5-HC vs 12.8% in SB5-LC).Table 1.Comparison of Primary PK Parameters between the TreatmentsPK ParameterTreatmentGeometric LSMeanRatio90% CIAUCinf (h·μg/mL)SB5-HC2616.10.9200.8262; 1.0239SB5-LC2844.3Cmax (μg/mL)SB5-HC4.10.9840.9126; 1.0604SB5-LC4.1ConclusionThis study demonstrated PK equivalence between SB5-HC and SB5-LC in healthy subjects. Both SB5-HC and SB5-LC were generally well tolerated with similar safety profiles.