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Response to: ‘Correspondence on: ‘Dupilumab as a novel steroid-sparing treatment for IgG4-related disease’ by Simpson et al’ by Ebbo et al
  1. Rachel S Simpson,
  2. Jason K Lee
  1. Toronto Allergists, Toronto, Ontario, Canada
  1. Correspondence to Rachel S Simpson, Toronto Allergists, Toronto, Ontario, Canada; rachel.simpson{at}

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We thank Ebbo et al for their interest in our case report1 and for providing their case of a patient with IgG4-related disease (IgG4-RD) whom they have also treated with dupilumab.2 Notably, Ebbo et al reported variability in the response to dupilumab compared with our patient. Our patient did have different clinical manifestations than that of Ebbo et al’s patient, as our patient had profound retroperitoneal and genitourinary fibrosis along with atopic dermatitis, asthma, allergic rhinoconjunctivitis, parotitis, and sinusitis while Ebbo et al’s patient presented with dacryoadenitis and sialadenitis in conjunction with allergic manifestations such as chronic rhinosinusitis with nasal polyps, asthma and urticaria. We are curious also to ask if the relationships between the variables presented in Figures C, D and E were statistically significant from their data.

In response to Ebbo et al’s belief that the response we have seen is confounded by initial use of prednisone, we would like to clarify that it has come to our attention post publication (29 December 2019), that the patient in our case did not take a single dose of prednisone due to undisclosed non-compliance, therefore making dupilumab the first-line treatment that was used. Due to the fact that the patient Ebbo et al described underwent rituximab therapy prior to dupilumab therapy, it is also possible that this added to the variability in the observed patient’s response compared with ours. It should also be noted that because Ebbo et al’s patient was on glucocorticoids for 3 months and then approximately 1 month a year before dupilumab treatment, the same argument can be made that perhaps this confounds their results. However, due to the variability in both clinical manifestations and prior treatments that can be seen in the IgG4-RD patient presented in comparison to ours, it can be understood why perhaps Ebbo et al’s patient may have not shown such complete resolution to their disease after dupilumab treatment.

We do find it interesting that Ebbo et al have reported their case with respect to a suboptimal clinical and radiological response to dupilumab 8 months after treatment. We believe it would be useful to provide information with respect to the 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-related involvement post-dupilumab treatment to compare to the pre-treatment score. We do believe Ebbo et al’s report shows valuable data with regards to the variability in responses to dupilumab that may take place in IgG4-RD and we wonder if it would be valuable to study IgG4-RD response to dupilumab in two separate groups through a large randomised clinical trial: dupilumab as a first-line treatment for IgG4-RD and dupilumab for patients that are refractory to conventional treatments such as glucocorticoids, immunosuppressants and/or rituximab for IgG4-RD. By studying both groups fully using well-detailed inclusion and exclusion criteria, we believe that the optimal place for dupilumab in the IgG4-RD treatment algorithm will be able to be identified, as well as dupilumab’s safety and efficacy for this condition will be thoroughly investigated.

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  • Handling editor Josef S Smolen

  • Contributors RSS undertook the primary duties in writing the manuscript. JKL oversaw the manuscript writing and edited the manuscript.

  • 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 JKL reports receiving research grants, clinical research trial funding and speaker fees from Novartis, Sano, Regeneron, Sano Genzyme, Astrazeneca, Genentech, Roche and GlaxoSmithKline as well as personal fees from ALK, grants and personal fees from Aralez, and grants and personal fees from Pediapharm.

  • 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 Commissioned; internally peer reviewed.

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