Psoriatic Oligoarthritis Intervention With Symptomatic thErapy

Arm 1: Control 'step-up' therapy in the cohort (MONITOR-PsA study). Therapy for the cohort is defined by standard practice in these PsA clinics following current international recommendations and National requirements for the prescription of biologic therapy. Whilst physician discretion is used, most commonly Initial therapy will be with methotrexate alone (15mg/week rising to 25mg/week as tolerated by week 8 of therapy) unless this is contraindicated. In cases of non-response or intolerance to methotrexate, participants will have an alternative DMARD (most commonly sulfasalazine or leflunomide) added or switched to at the discretion of the rheumatologist. In cases of failure of two DMARDs, treatment can be escalated to biologic therapy as per National Institute for Health and Clinical Excellence (NICE) recommendations usually with a TNF inhibitor as first line. If the requisite disease activity is not met or if there are contraindications to biologics, alternative DMARD combinations will be used. Further details are available in the PsA clinic treatment protocol which is Appendix D in the MONITOR-PsA protocol. Arm 2: Symptomatic therapy arm. The intervention will delay standard treatment with disease-modifying anti-rheumatic drugs (DMARDs) and use local glucocorticoid injections to affected joints instead. Oral non-steroidal anti-inflammatory drugs (NSAIDs) will also be allowed as concomitant medication as indicated for individuals. Local glucocorticoid injections will include injections with methylprednisolone or triamcinolone. All active joints will be treated with glucocorticoid injections. Glucocorticoid injections can be either be given as an intra-articular injection to an inflamed joint or as an intra-muscular injection if multiple joints are involved. If any joint requires more than 2 local injections of glucocorticoid within a 6 month period, then the patient is deemed to have failed symptomatic therapy and will be withdrawn from the treatment protocol and be treated as per usual care (in most cases with DMARD therapy). If Participants require DMARD therapy, they will be offered rescue therapy as per usual clinical care but will be asked to continue with data collection for the trial. This is to ensure that sufficient data is collected for the trial but risks in delaying treatment to the individual are mitigated.