Table 1 Study objectives and endpoints

Objectives	Endpoints
Primary
• To evaluate the efficacy of guselkumab treatment in patients with active PsA by assessing the reduction in signs and symptoms of PsA.	Proportion of patients with ACR20 response at week 24: • ≥20% improvement from baseline in both swollen joint count (66 joints) and tender joint count (68 joints) AND • ≥20% improvement from baseline in three of the following assessments: ° Patient pain (VAS) ° PtGA (arthritis, VAS) ° PhGA (VAS) ° HAQ-DI ° Serum CRP level
Major secondary
• To evaluate the inhibition of progression of structural damage in patients with active PsA.	Mean change from baseline in PsA-modified vdH-S score at week 24.
Other secondary
• To evaluate the safety of guselkumab in patients with active PsA.	For the duration of the study, through week 60^a: • Frequency and type of AEs, SAEs, reasonably related AEs, AEs leading to discontinuation of study intervention, infections, and injection-site reactions. • Frequency of laboratory abnormalities (chemistry, hematology), maximum toxicity CTCAE 5.0 grades.
• To evaluate the PK and immunogenicity of guselkumab in patients with active PsA.	For the duration of the study, through week 60^a: • Mean/median serum guselkumab concentration. • Summary of incidence of antibodies to guselkumab.

Additional assessments - see Additional file 3
ACR20 ≥20% improvement in American College of Rheumatology criteria, AE adverse event, CRP C-reactive protein, CTCAE 5.0 Common Terminology Criteria for Adverse Events, HAQ-DI Health Assessment Questionnaire Disability Index, Patient pain patient’s assessment of pain, PtGA Patient’s Global Assessment of Disease Activity, PhGA Physician’s Global Assessment of Disease Activity, PK pharmacokinetics, PsA psoriatic arthritis, SAE serious adverse event, VAS visual analog scale, vdH-S van der Heijde-Sharp
^aThrough week 168 for patients who enter the long-term extension

ISSN: 1745-6215