Arthritis prevention in the pre-clinical phase of RA with abatacept (the APIPPRA study): a multi-centre, randomised, double blind, parallel group placebo-controlled clinical trial Protocol

Abstract Trial design: We present a study protocol for a multi-centre, randomised, double blind, parallel group, placebo-controlled trial that seeks to test the feasibility, acceptability and effectiveness of a 52-week period of treatment with the first-in-class costimulatory blocker abatacept for preventing or delaying the onset of inflammatory arthritis. Methods: The study aimed to recruit 206 male or female subjects from the secondary care hospital setting across the UK and the Netherlands. Participants aged 18 or over who report inflammatory sounding joint pain (clinically suspicious arthralgia) and who are found to be positive for serum autoantibodies associated with RA were eligible for enrolment. All study subjects were randomised to receive weekly injections of investigational medicinal product (IMP), either abatacept or placebo treatment over a 52-week period. Participants were then followed up for a further 52 weeks. The primary endpoint was defined as the time to development of ≥ 3 swollen joints, or to the fulfilment of the 2010 ACR/EULAR classification criteria for RA using swollen but not tender joints, whichever endpoint was met first. In either case, swollen joints were confirmed by ultrasonography. Participants, care givers, and those assessing the outcomes were all blinded to group assignment. Clinical assessors and ultrasonographers were also blinded to each other’s assessments for the duration of the study. Conclusions: There is limited experience of the design and implementation of trials for the prevention of inflammatory joint diseases. We discuss the rationale behind choice and duration of treatment, the challenges associated with defining the “at risk” state, and offer pragmatic solutions in the protocol to enrolling subjects at risk of RA. Trial registration: Current Controlled Trials, ID: ISRCTN46017566. Registered on 04 July 2014.