Abstract
INTRODUCTION: The aim of this sub-study was to evaluate injection success of patients with rheumatoid arthritis (RA) and their caregivers administering the adalimumab (ADL) biosimilar, PF-06410293 (ADL-PF: adalimumab-afzb; Abrilada(®)/Amsparity(®)/Xilbrilada(®)) by prefilled pen (PFP) during the open-label treatment period in year two (weeks 52-78) of a phase 3 multinational, double-blind, clinical study (NCT02480153) comparing ADL-PF and reference ADL (Humira(®)) sourced from the EU. METHODS: This sub-study included adult patients with active RA not adequately controlled by methotrexate. Patients received subcutaneous ADL-PF 40 mg by prefilled syringe (PFS) at weeks 52 and 54, then six biweekly doses (weeks 56-66) of ADL-PF 40 mg each via a single-use PFP device. Training was given on first injection at week 56; all injections were given by patients/caregivers. The primary endpoint was delivery system success rate (DSSR): the percentage of participants (i.e., actual PFP user) achieving delivery success for each of the six attempted PFP injections. Injection success was recorded by the observer (Observer Assessment Tool) and participant (Participant Assessment Tool). RESULTS: In total, 50 patients with no experience self-injecting with an autoinjector/injection pen were included (74.0% female; mean age at screening, 54.9 years; mean RA duration, 8.0 years). Of these, 49 (98.0%) completed the sub-study and 46 (92.0%) received all six PFP injections. Overall DSSR (n = 294 injections) across visits was 100% (95% CI 92.0-100.0%). Complete injection was confirmed following inspection of 292 used and returned PFPs. A total of 47/49 (95.9%) participants who completed the sub-study elected to continue study treatment using PFP injections, rather than switching back to the PFS. CONCLUSIONS: All actual PFP users could safely and effectively administer ADL-PF by PFP at each visit, and nearly all participants who completed the sub-study elected to continue study treatment using PFP injections. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02480153; EudraCT number: 2014-000352-29.