Correspondence on ‘Long-term efficacy and safety of canakinumab in patients with colchicine-resistant familial Mediterranean fever: results from the randomised phase III CLUSTER trial’
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* Hasan Satış
* Ergin Aydemir
* Kerem İzmirlioğlu
* Abdurrahman Tufan

*   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.

## Ethics statements

### Patient consent for publication

Not required.

## Footnotes

*   Contributors All authors are contributed to the manuscript equally.

*   Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

*   Competing interests None declared.

*   Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

*   Provenance and peer review Not commissioned; internally peer reviewed.

## References

1.   Ozen S , Ben-Cherit E , Foeldvari I , et al . Long-term efficacy and safety of canakinumab in patients with colchicine-resistant familial Mediterranean fever: results from the randomised phase III cluster trial. Ann Rheum Dis 2020;79:1362–9.[doi:10.1136/annrheumdis-2020-217419](http://dx.doi.org/10.1136/annrheumdis-2020-217419) pmid:32571870 
    
    [Abstract/FREE Full Text](http://ard.bmj.com/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTE6ImFubnJoZXVtZGlzIjtzOjU6InJlc2lkIjtzOjEwOiI3OS8xMC8xMzYyIjtzOjQ6ImF0b20iO3M6Mjg6Ii9hbm5yaGV1bWRpcy84MS8xMi9lMjU2LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

2.   Babaoglu H , Armagan B , Bodakcı E , et al . Factors associated with damage in patients with familial Mediterranean fever. Clin Exp Rheumatol 2020. [Epub ahead of print: 18 Jun 2020].pmid:http://www.ncbi.nlm.nih.gov/pubmed/32573410 
    
    

3.   Babaoglu H , Armagan B , Bodakcı E , et al . Predictors of persistent inflammation in familial Mediterranean fever and association with damage. Rheumatology 2020. doi:[doi:10.1093/rheumatology/keaa378](http://dx.doi.org/10.1093/rheumatology/keaa378). [Epub ahead of print: 10 Aug 2020].pmid:http://www.ncbi.nlm.nih.gov/pubmed/32778893