Treatment Therapies for Chronic CPP Crystal Inflammatory Arthritis

Clinicians at European centers with expertise in treating chronic calcium pyrophosphate (CPP) crystal inflammatory arthritis prescribed daily colchicine most frequently as first-line therapy, with sustained treatment efficacy reported among 33% to 50% of patients, according to study findings published in Rheumatology.

Investigators aimed to characterize treatments used for management of chronic CPP crystal inflammatory arthritis within 7 European centers and to determine treatment retention, efficacy, and safety.

A retrospective cohort study was conducted including adult patients diagnosed with chronic CPP crystal inflammatory arthritis treated from January 2015 through April 2021. Follow-up visits were conducted at 3, 6, 12, and 24 months.

Investigators defined chronic CPP crystal inflammatory arthritis as persistent CPP crystal inflammatory arthritis lasting beyond 3 months and/or recurrent (>2 episodes/year) acute episodes of CPP crystal arthritis.

A total of 194 treatments were initiated during the study period (mean number of treatments/patient, 1.8). Most common treatments included colchicine (86 treatments), methotrexate (36 treatments), anakinra (27 treatments), and tocilizumab (25 treatments).

Colchicine was prescribed most frequently as a first-line therapy (73/86 treatments; 84.9%), at doses of 1 mg once per day (57.8% of treatments) and 0.5 mg once per day (34% of treatments). Methotrexate was most commonly prescribed as a second-line treatment (22/36 treatments; 66.1%; mean dose, 14.7 mg/week).

Anakinra (mean dose at initiation, 93.8 mg/day) and tocilizumab (mean subcutaneous dose at initiation, 162 mg/week; mean intravenous dose at initiation, 8 mg/kg/month) were often prescribed as second-or third-line treatments. They were combined with methotrexate and/or with colchicine in 9.6% and 34.6% of patients, respectively.

Among patients treated with methotrexate, 44.4% retained treatment at 24-months, as did 40.0%, 29.1%, and 18.5% of those treated with tocilizumab, colchicine, and anakinra, respectively.

A total of 74.4%, 63.9%, 81.5%, and 60.0% of patients treated with colchicine, methotrexate, anakinra, and tocilizumab discontinued treatment.

Adverse events accounted for 9 patients (14.1%) discontinuing treatment with colchicine, 1 patient (4.3%) discontinuing methotrexate, 7 patients (31.8%) discontinuing anakinra, and 3 patients (20.0%) discontinuing tocilizumab, with other discontinuations largely due to inefficacy (34.4% colchicine; 30.4% methotrexate; 27.3% anakinra; 33.3% tocilizumab) or loss to follow-up.

Throughout follow-up, efficacy outcomes were not significantly different between treatments.

Study limitations included the retrospective design, possible selection bias, and lack of standardized outcome measures.

The study authors concluded, “Our results call for adequately powered clinical trials to evaluate the efficacy of methotrexate, colchicine and biologics in persistent CPP crystal inflammatory arthritis and recurrent acute CPP crystal inflammatory arthritis, and a harmonisation of outcome measures used in their management.”