‘Not all drugs (and route) are same’
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* Abhishek Arvind Zanwar

*   Systemic Vasculitis
*   Treatment
*   Disease Activity

I read with great interest, study by French vasculitis group, the *MAINRITSAN 2* trial.1 The results of this trial again underline our limitations for search of biomarker, which can predict relapse of antineutrophil cytoplasmic autoantibodies (ANCA)-associated vasculitis. I have few concerns about details and analysis regarding induction regime used in the patient study group.

First is about the data provided by authors about the use of cyclophosphamide for remission induction. Previous study has shown that route and cumulative dose used for remission induction can affect relapse in long term.2 Risk of relapse is significantly lower when daily oral cyclophosphamide was used for remission induction as against pulse intravenous cyclophosphamide. It would have been clearer if authors had given and compared details of cyclophosphamide therapy used for the last flare, especially when more than 60% of group of participants have received the drug.

Second, a previous study has suggested that ANCA titres predicts relapse in patients in whom rituximab was used for remission induction but this observation was not seen in patient treated with cyclophosphamide.3 In current study group, use of cyclophosphamide was more frequent than rituximab, which may have affected results of study. May be subset analysis between these two groups can be more useful.

## Footnotes

*   Handling editor Josef S Smolen

*   Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

*   Competing interests None declared.

*   Patient consent Not required.

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

## References

1.   Charles P , Terrier B , Perrodeau É , et al . French Vasculitis Study Group. Comparison of individually tailored versus fixed-schedule rituximab regimen to maintain ANCA-associated vasculitis remission: results of a multicentre, randomised controlled, phase III trial (MAINRITSAN2). Ann Rheum Dis 2018;77:1143–9.[doi:10.1136/annrheumdis-2017-212878](http://dx.doi.org/10.1136/annrheumdis-2017-212878) 
    
    [Abstract/FREE Full Text](http://ard.bmj.com/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTE6ImFubnJoZXVtZGlzIjtzOjU6InJlc2lkIjtzOjk6Ijc3LzgvMTE0MyI7czo0OiJhdG9tIjtzOjI2OiIvYW5ucmhldW1kaXMvNzgvOC9lNzQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

2.   Harper L , Morgan MD , Walsh M , et al . Pulse versus daily oral cyclophosphamide for induction of remission in ANCA-associated vasculitis: long-term follow-up. Ann Rheum Dis 2012;71:955–60.[doi:10.1136/annrheumdis-2011-200477](http://dx.doi.org/10.1136/annrheumdis-2011-200477) 
    
    [Abstract/FREE Full Text](http://ard.bmj.com/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTE6ImFubnJoZXVtZGlzIjtzOjU6InJlc2lkIjtzOjg6IjcxLzYvOTU1IjtzOjQ6ImF0b20iO3M6MjY6Ii9hbm5yaGV1bWRpcy83OC84L2U3NC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

3.   Fussner LA , Hummel AM , Schroeder DR , et al . Factors determining the clinical utility of serial measurements of antineutrophil cytoplasmic antibodies targeting proteinase 3. Arthritis Rheumatol 2016;68:1700–10.[doi:10.1002/art.39637](http://dx.doi.org/10.1002/art.39637)