Background/Purpose: Risankizumab (RZB), a fully humanized IgG1 monoclonal antibody inhibitor of IL-23, is a therapeutic agent approved for the treatment of active psoriatic arthritis (PsA) in adults. Results from the KEEPsAKE 1 and KEEPsAKE 2 phase 3 trials demonstrated superior efficacy and safety of RZB compared with placebo in patients with active PsA. This post hoc, integrated analysis evaluates the long-term efficacy of RZB across clinically relevant patient subgroups at 52 weeks of treatment.

Methods: KEEPsAKE 1 (NCT03675308) and KEEPsAKE 2 (NCT03671148) are ongoing, multicenter, randomized, double-blind, placebo-controlled, phase 3 studies with open-label periods. Patients with active PsA and an inadequate response or intolerance to a conventional synthetic disease-modifying, anti-rheumatic drug (csDMARD; KEEPsAKE 1 and 2) and/or biologic therapy (KEEPsAKE 2) were randomized (1:1) to receive RZB 150 mg or placebo at weeks 0, 4, and 16. At week 24, patients who were initially randomized to RZB received blinded placebo, and patients who were initially randomized to placebo received the first dose of blinded RZB. All patients received open-label RZB 150 mg at week 28 and every 12 weeks thereafter to week 208. This post hoc, integrated analysis evaluated efficacy (proportion of patients who achieved ≥ 20% improvement in American College of Rheumatology criteria [ACR20] at week 52) by baseline demographics (age [< 65 years, ≥ 65 years, ≥ 65 to < 75 years, ≥ 75 years], sex [male, female], race [White, non-White], body mass index [< 25 kg/m², ≥ 25 to < 30 kg/m², ≥ 30 kg/m²]), disease characteristics (PsA duration [≤ 5 years, > 5 to ≤ 10 years, > 10 years], baseline high-sensitivity C-reactive protein [< 3 mg/L, ≥ 3 mg/L]), and prior/concomitant therapy exposure (concomitant csDMARD at baseline [any csDMARD, any methotrexate, none], prior biologic use [yes, no]).

Results: Among 1408 patients initially randomized to receive either RZB 150 mg or placebo, 1354 continued into the open-label periods; 1235 patients were still ongoing at the time of data cutoff. In this analysis, a generally consistent proportion of patients initially randomized to receive continuous RZB achieved ACR20 at week 52, regardless of age, sex, race, body mass index, PsA duration, baseline high-sensitivity C-reactive protein levels, concomitant use of csDMARDs at baseline, or prior use of biologic therapy. Patients who were switched from placebo to RZB also achieved similar ACR20 response rates at week 52 with similar consistent efficacy across subgroups.

Conclusion: Patients randomized to receive continuous RZB 150 mg treatment achieved consistent efficacy across patient demographic, disease characteristic, and prior treatment history subgroups following 52 weeks of treatment. These efficacy results support long-term use of RZB in patients across multiple patient and psoriatic disease characteristics.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/risankizumab-rzb-demonstrates-long-term-efficacy-across-subgroups-in-patients-with-active-psoriatic-arthritis-psa-a-post-hoc-integrated-analysis-from-the-phase-3-keepsake-1-and-keepsake-2-stud/