• amyloidosis
• familial Mediterranean fever
• interleukin 1 receptor antagonist protein
• inflammation

We read with great interest the article “Long-term efficacy and safety of canakinumab in patients with colchicine-resistant familial Mediterranean fever: results from the randomised phase III CLUSTER trial” by Özen et al.1 This article makes a remarkable contribution to treatment in patients with colchicine-resistant familial Mediterranean fever (FMF), which shows a great remission rate with minimal side effects. However, there are some aspects that need to be clarified and discussed.

First, it would be better to report the dominant attack-type of the patients because we think musculoskeletal type attacks, especially mild ones, could be skipped and not remembered by the patients when they are admitted to outpatient control. These attacks are also associated with increased damage.2 Second, there is an inconsistency regarding patient number in canakinumab dosage group between figure 1 and text in the results section. It was written as “44 patients received <2700 mg canakinumab and 16 received ≥2700 mg”. However, in the figure, it was stated as 42 and 15, respectively. Baseline median C reactive protein (CRP) levels were higher than normal, and we wonder whether the increased CRP levels are persistent. It was shown that persistent inflammation was related to the increased risk of amyloidosis, kidney dysfunction and proteinuria,3 but the latter was not discussed in the manuscript. We would like to also know the effect of canakinumab on the proteinuria of those patients.

We appreciate the work of Özen et al to highlight the treatment of patients with colchicine-resistant FMF. We believe that this comprehensive study will help the clinician to manage these high-risk group of patients.