Low rates of radiographic progression associated with clinical efficacy following up to 2 years of treatment with guselkumab: results from a phase 3, randomised, double-blind, placebo-controlled study of biologic-naïve patients with active psoriatic arthritis

OBJECTIVE: Evaluate relationship between radiographic progression and clinical outcomes in post hoc analyses of patients with psoriatic arthritis (PsA) receiving up to 2 years of guselkumab therapy in the phase 3, placebo-controlled, randomised trial, DISCOVER-2. METHODS: Biologic-naïve adults with active PsA (≥5 swollen joints /≥5 tender joints; C reactive protein ≥0.6 mg/dL) were randomised to guselkumab 100 mg every 4 weeks (Q4W); guselkumab 100 mg at week 0, week 4, then every 8 weeks (Q8W); or placebo→guselkumab 100 mg Q4W (week 24). Radiographs (hands/feet) at week 0, week 24, week 52 and week 100 were scored via PsA-modified van der Heijde-Sharp (vdH-S) methodology. In these post hoc analyses, mean changes in vdH-S scores were summarised according to achievement of American College of Rheumatology 20/50/70 response; low disease activity (LDA) defined by Disease Activity in Psoriatic Arthritis (DAPSA) ≤14 or Psoriatic ArthritiS Disease Activity Score (PASDAS) ≤3.2, or minimal/very low disease activity (MDA/VLDA); and normalised physical function (Health Assessment Questionnaire-Disability Index (HAQ-DI) ≤0.5). Response rates for achieving MDA/VLDA and each component were determined among patients with and without radiographic progression (change in total vdH-S score >0.5). No formal hypothesis testing was performed. RESULTS: 664 of 739 treated patients in DISCOVER-2 continued study treatment at week 52 and were included in these analyses. Mean changes in vdH-S scores from weeks 0 to 100 among all patients in the Q4W and Q8W groups were 1.7 and 1.5, respectively. Among all guselkumab-randomised patients, those who achieved ACR20/50/70, DAPSA LDA, PASDAS LDA, MDA, VLDA and HAQ-DI ≤0.5 (normalised physical function) had smaller mean changes in vdH-S scores than did non-responders at week 52 (0.2–1.2 vs 1.7–4.1) and week 100 (0.3–1.2 vs 2.0–4.6). Relative to patients with radiographic progression, those without progression were more likely to achieve the MDA criteria related to swollen and tender joint counts, patient-reported pain and global assessment, and normalised physical function through week 100. CONCLUSION: In these post hoc analyses, the achievement of low levels of disease activity, including MDA, was associated with diminished rates of radiographic progression observed in patients receiving up to 2 years of guselkumab. Radiographic non-progressors were more likely to achieve patient-reported MDA criteria of minimal pain and normalised physical function compared with radiographic non-responders. TRIAL REGISTRATION NUMBER: NCT03158285.