Efficacy and tolerance of anakinra in acute calcium pyrophosphate crystal arthritis: a retrospective study of 33 cases.

Calcium pyrophosphate (CPP) deposition is a frequent joint disease with increased prevalence in older people in whom treatment of acute CPP arthritis with conventional therapies such as colchicine or non-steroidal anti-inflammatory drugs could be contraindicated or not used at an optimal dose. As recommended in gout, anakinra might represent an alternative treatment for arthritis. We aimed to analyze the efficacy and safety of anakinra in acute CPP arthritis in a large reported series. We retrospectively included all patients receiving anakinra for acute CPP arthritis between January 2011 and 2017. The following data were collected before and 4 days after the first anakinra injection: swollen joint count (SJC), tender joint count (TJC), pain score on a visual analog scale (VAS, 0-100 mm), and C-reactive protein (CRP) level. A good response was defined according the evaluation of the physician. We included 33 patients (24 women; mean age 79.2 ± 12.8 years). The number of good responders was 27 (81.8%). At day 4, patients showed decreased mean VAS pain score (from 64.8 ± 26.5 to 21.2 ± 19.7 mm, p < 0.0001), TJC (5.8 ± 5.0 to 1.0 ± 1.0, p < 0.0001), SJC (3.9 ± 2.7 to 0.9 ± 1.0, p < 0.0001), and CRP level (116.1 ± 71.6 to 26.0 ± 23.1 mg/l, p < 0.0001). Anakinra was well tolerated, without skin complications. Only one patient had pneumonitis that was resolved with oral antibacterial agents. Anakinra could be a relevant alternative for managing acute CPP arthritis when conventional therapies are ineffective or contraindicated.