The population pharmacokinetics (PK) of risankizumab and exposure-response relationships for efficacy and safety in patients with Crohn's disease (CD) were characterized using data from phase II and III studies to support dosing regimen selection. A two-compartment model with first-order absorption and first-order elimination adequately described risankizumab PK. Covariates including sex, baseline fecal calprotectin, corticosteroid use, baseline creatinine clearance, body weight, and baseline albumin were statistically correlated with risankizumab clearance, but their impact on exposure was not clinically relevant for efficacy or safety. Exposure-response analyses showed that exposures associated with the 600 mg intravenous (i.v.) induction dose at Weeks 0, 4, and 8 achieved a near maximal response for all efficacy end points evaluated, with negligible added benefit from the 1,200 mg i.v. regimen. By Week 52 of the maintenance treatment, trends of higher responses were observed for the exposure range associated with the 360 mg subcutaneous (s.c.) every-8-weeks (Q8W) regimen for most of the evaluated efficacy end points, particularly for the more stringent end points, such as endoscopic remission and ulcer-free endoscopy. Exposure-response analyses for safety did not identify any apparent relationship between exposure and safety. These results supported the final dose recommendation of 600 mg i.v. at Weeks 0, 4, and 8, followed by 360 mg s.c. at Week 12 and Q8W thereafter in patients with CD.Crohn's disease (CD) is a chronic inflammatory bowel disease that can affect any segment of the gastrointestinal tract, causing symptoms such as abdominal pain, fatigue, prolonged diarrhea with or without serious bleeding, weight loss, and fever. 1 The exact cause of CD is unknown, but it is hypothesized that an interplay of the patient's genetics, microbiome, immune response,

Introduction: Risankizumab is an anti-IL23 monoclonal antibody approved for the treatment of moderate to severe plaque psoriasis and active psoriatic arthritis (PsA). This work characterizes the pharmacokinetics of risankizumab in PsA compared with psoriasis and evaluates the efficacy and safety exposure-response relationships in PsA. Methods: The population pharmacokinetic analyses included data from 1527 participants that originated from one phase 1 healthy participant study, one phase 2 dose-ranging study in patients with PsA with an open-label extension study, and two pivotal phase 3 studies in patients with PsA, where the clinical regimen of risankizumab 150 mg administered subcutaneously (SC) at weeks 0, 4, and every 12 weeks thereafter was compared with placebo.