Population pharmacokinetics and exposure‐response modeling analyses of guselkumab in patients with psoriatic arthritis

Guselkumab is an anti‐interleukin‐23 human monoclonal antibody effective in treating psoriatic arthritis (PsA). To characterize the pharmacokinetics (PKs) and exposure‐response relationship of guselkumab in PsA, population PKs, and exposure‐response modeling, analyses were conducted using data from pivotal phase III studies of subcutaneous guselkumab in patients with PsA. The observed serum concentration‐time data of guselkumab were adequately described by a one‐compartment linear PK model with first‐order absorption and elimination. Covariates identified as contributing to the observed guselkumab PK variability were body weight and diabetes comorbidity; however, the magnitude of the effects of these covariates was not considered clinically relevant, and dose adjustment was not warranted for the patient population investigated. Positive exposure‐response relationships were demonstrated with landmark and longitudinal exposure‐response analyses between guselkumab exposure and clinical efficacy end points (American College of Rheumatology [ACR] 20%, 50%, and 70% improvement criteria and Investigator’s Global Assessment [IGA] of psoriasis) at weeks 20 and/or 24, with no clinically relevant differences observed in improvement of PsA signs and symptoms between the two guselkumab treatment regimens evaluated (100 mg every 4 weeks or 100 mg at weeks 0 and 4, then every 8 weeks). Baseline Disease Activity Score in 28 joints (DAS28), Psoriasis Area and Severity Index (PASI) score, and/or C‐reactive protein level were identified as influencing covariates on guselkumab exposure‐response model parameters. These results provide a comprehensive evaluation of subcutaneous guselkumab PKs and exposure‐response relationship that supports the dose regimen of 100 mg at weeks 0 and 4, then every 8 weeks in patients with PsA.