Background: The pharmacokinetics of golimumab, a human monoclonal antibody that inhibits the activity of tumor necrosis factor α, after a single subcutaneous (SC) or intravenous (IV) administration have been previously studied.

Objectives: The purpose of this study was to assess the pharmacokinetics of golimumab after multiple SC or IV administrations in patients with active rheumatoid arthritis (RA). The effect of concomitant methotrexate (MTX) use on golimumab pharmacokinetics was evaluated.

Methods: In this open-label, randomized, Phase I study, 49 adult patients with RA received SC golimumab 100 mg (n = 33) every 4 weeks through week 20 or IV golimumab 2 mg/kg (n = 16) at weeks 0 and 12. Serial blood samples were collected, and serum golimumab concentration was measured with an electrochemiluminescent immunoassay. Golimumab pharmacokinetic parameters were derived with the use of a noncompartmental analysis. Adverse events were monitored at every visit.

Results: The population was predominantly Caucasian (84%) and female (76%), and the median age was 57 years. After SC golimumab administration, the serum golimumab concentration achieved steady state by ∼12 weeks with mean trough serum concentrations ranging from 1.15 to 1.24 μg/mL. After the final 30-minute IV infusion of golimumab 2 mg/kg, the mean (SD) clearance (CL) was 7.5 (2.6) mL/d/kg. The mean terminal half-life after SC and IV administrations was ∼13 days. The mean absolute bioavailability for SC golimumab was estimated to be 53%. The geometric mean of golimumab CL/F in patients with and without concomitant MTX use was 13.9 and 21.2 mL/d/kg, respectively, and the geometric mean ratio of CL/F was 65.5% (90% CI: 45.2%-94.9%, P = 0.06). Golimumab was generally well tolerated. No malignancies or deaths occurred during the study.

Conclusions: Pharmacokinetics of golimumab were consistent after SC or IV administration in this population of patients with RA. Golimumab was well tolerated and no unexpected adverse events were observed in this trial.

Trial registration: ClinicalTrials.gov NCT01362153.