Background/Purpose: Calcium pyrophosphate deposition disease (CPPD) is a heterogeneous disease that can manifest as acute or chronic arthritis. Treatment options for chronic forms of the disease are limited. An open-label study of 11 patients treated ‘off-label’ with tocilizumab (TCZ) for a chronic inflammatory form of CPPD refractory to conventional treatments previously reported encouraging results. Since then, a larger number of patients have received TCZ and these retrosepctive results are reported here.

Methods: We report here the results of all patients treated with TCZ for a chronic inflammatory form of CPPD at two university hospitals with expertise in the management of microcrystalline rheumatic diseases. Patients were included if they had received at least 3 months of TCZ, and their data were retrieved retrospectively from medical records. Disease characteristics, previous treatments received, TCZ treatment efficacy and safety, discontinuations and reasons for discontinuation of TCZ were analysed.

Results: A total of 55 patients (mean age +/- SD: 68.3 +/- 12.5 years; 65.4% female) were treated with TCZ for chronic (n=39), recurrent acute (n=14; 0-4 attacks/month) or mixed (n=2) CPPD. CPPD was primary in the majority of cases or secondary to hypomagnesemia (n=5), hereditary haemochromatosis HFE (n=3), primary hyperparathyroidism (n=2) or ANKH mutation (n=1). The median disease duration at the time of TCZ initiation was 4.75 years (min-max: 0.3-48.7). All patients had received colchicine (0.5-1 mg/day), 20 patients had received prednisone (5-45 mg/day) and 24 patients had received anakinra, which later was either ineffective (n=13) or poorly tolerated (n=11).

TCZ was administered intravenously in 46 patients and subcutaneously in 9 patients. The mean VAS for pain (0-100 mm) was 60.8 +/- 21.3 mm at baseline, decreasing to 44.1 +/- 24.0 at month 3 and 37.4 +/- 2.9 at month 6. During follow-up, 22 patients reported an adverse event, including 9 cytopenias, 6 transaminase elevations, 3 infections (2 severe) and 3 injection site reactions. A total of 22 patients (40%) discontinued TCZ after a median of 7.0 months (min-max: 1-48.6), 13 due to lack of efficacy and 9 due to intolerance. The median duration of treatment for those who remained on treatment (n=33) was 26.0 months (min-max: 3-76.5). Of those who started on the IV route, 10 patients switched to the SC route, 7 of whom eventually returned to the IV route due to loss of efficacy. TCZ cessation was attempted in 8 patients, 5 of whom relapsed and eventually returned to TCZ.

Conclusion: Tocilizumab improved control of chronic inflammatory forms of CPPD in more than 2/3 of patients who failed or were intolerant to usual therapies. These retrospective results confirm the need for a randomised controlled trial comparing TCZ with placebo in this indication.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/efficacy-and-safety-of-tocilizumab-in-the-treatment-of-chronic-inflammatory-forms-of-cppd-retrospective-study-of-55-cases/