Characteristics and medication use of psoriasis patients who may or may not qualify for randomized controlled trials

Abstract

BACKGROUND: Clinical trials impose exclusion criteria that may limit the generalizability of results. OBJECTIVES: To (a) determine the percentage of real-world patients who would qualify for psoriasis randomized controlled trials; (b) ascertain differences between moderate-to-severe psoriasis patients who would be eligible, ineligible, or potentially eligible for clinical trials; and (c) compare their biologic treatment patterns. METHODS: Moderate-to-severe psoriasis patients were identified from the U.S. Department of Defense health care database from January 1, 2008, to October 31, 2013. Eligibility classification for psoriasis trials was based on common trial exclusion criteria involving medical conditions and recent treatment history. Patient characteristics and treatment patterns of 4 biologics (adalimumab, etanercept, infliximab, and ustekinumab) were compared between groups. Adherence was measured by medication possession ratio and persistence as continuous time on drug with ≤90-day gap between supply times. RESULTS: Among 16,284 qualifying psoriasis patients, 4,677 (28.7%) were medically ineligible, and 8,466 (52.0%) had ineligibility-related treatments that could be stopped prior to trial entry; the latter patients were considered potentially eligible for psoriasis trials. Common reasons for medical ineligibility included malignancies and hematologic disorders; treatment ineligibilities included use of topical corticosteroids and phototherapy. Medically ineligible patients were older and had more comorbidities, while potentially eligible patients were younger and healthier than trial-eligible patients. Most treatment patterns were similar across groups, except that, compared with the trial-eligible group, medically ineligible patients had greater adherence to infliximab and potentially trial-eligible patients had greater adherence and persistence to adalimumab. CONCLUSIONS: This large real-world study found that patients who may be ineligible for psoriasis trials differ in important respects (e.g., comorbidities, prior treatments) from their trial-eligible counterparts. Regardless of their differences at baseline, adherence, persistence, and switching of biologic medications are largely similar, with few differences noted among groups.