Compared with placebo, treatment with filgotinib may result in significantly improved health-related quality of life in patients with active psoriatic arthritis (PsA), according to research results published in Rheumatology.

To evaluate the effect of filgotinib vs placebo in patients with PsA, researchers used data from the EQUATOR (A Study to Assess Efficacy and Safety of Filgotinib in Active Psoriatic Arthritis; ClinicalTrials.gov Identifier: NCT03101670) study, a multicenter, double-blind, placebo-controlled phase 2 trial, which assessed drug efficacy of patients’ health-related quality of life using the PsA Impact of Disease 9 questionnaire (PsAID9).

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Patients in the EQUATOR study were randomly assigned 1:1 to receive either filgotinib 200 mg or a matching placebo once daily for 16 weeks. Assessments were conducted on day 1 and at weeks 1, 2, 4, 8, 12, 16, and 20.

In total, 131 patients were enrolled in the study (filgotinib, n=65; placebo, n=66), with similar baseline demographic and disease characteristics across groups. At baseline, mean PsAID9, 36-Item Short-Form Survey (SF-36) Physical Component Summary (PCS), and SF-36 Mental Component Summary (MCS) scores were similar between the 2 groups.

Investigators evaluated PsAID9 in all patients. Compared with placebo, filgotinib “significantly improved” PsAID9 scores. Between baseline and week 4, mean change in PsAID9 scores were -1.9±1.6 and -0.5±1.8 in the treatment and placebo groups, respectively (least squares mean [LSM] difference, -1.45; 95% CI, -2.02 to -0.89; P <.0001). At week 16, the mean change was -2.3±1.8 and -0.8±2.2, respectively (LSM difference, -1.48; 95% CI, -2.12 to -0.84; P <.0001). In addition, significant improvements were noted in all individual PsAID domains at week 16.

Significantly more patients in the filgotinib group achieved minimal clinically important improvement (MCII) in PsAID9 total store, compared with patients in the placebo group at weeks 4 and 16 (26.2% vs 8.6% and 42.6% vs 17.2%). This remained true even when alternative MCII definitions were applied.

Compared with placebo, filgotinib therapy also resulted in significantly improved SF-36 PCS scores at weeks 4 and 16. At week 4, mean change from baseline was 4.9±5.9 and 1.5±6.2 in each group; at week 16, the change was 7.4±6.6 and 2.4±6.6, respectively (LSM difference, 3.08 and 4.67, respectively).

At week 16, significant improvements were noted in all SF-36 physical health domains.

In terms of SF-36 MCS, no significant improvement was noted in the filgotinib group compared with the placebo group. Significantly more patients achieved PCS patient-accepted symptom status at week 16 in the filgotinib group, but no statistically significant difference was noted in MCS patient-accepted symptom status.

Researchers observed a moderate to strong negative statistically significant correlation between PsAID9 and both SF-36 PCS and MCS scores at weeks 4 and 16 in both treatment groups.

One study limitation was the mixed population, including patients who were antitumor necrosis factor-α therapy-naive and exposed.

“[T]o our knowledge the phase 2 EQUATOR study is the first [randomized controlled trial] in patients with active PsA to report PsAID9 data,” the researchers concluded. “These data also support the use of PsAID9 in measuring patient-relevant [health-related quality of life] domains in PsA clinical studies.”

Disclosure: This clinical trial was supported by Galapagos NV. Several study authors report affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Orbai A-M, Ogdie A, Gossec L, et al. Effect of filgotinib on health-related quality of life in active psoriatic arthritis: a randomized phase 2 trial (EQUATOR) [published online October 18, 2019]. Rheumatology. doi:10.1093/rheumatology/kez408