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.