Reply to: intravenous immunoglobulin (Gamunex® 10%) is licensed for the treatment of severe acute exacerbations of myasthenia gravis

We would like to thank Camps et al. [1] for the very constructive comments.

In our Editorial ‘What are the pharmacotherapeutic considerations for the treatment of myasthenia gravis?’ published in Expert Opinion on Pharmacotherapy in September 2022 [2] we discussed about current treatment strategies for myasthenia gravis (MG). The aim of our editorial was to highlight the recent developments in MG treatment options, especially regarding chronic therapy, which has relied for many years on prednisone and non-steroidal immunosuppressants (NSITs), which have many burdensome side effects and, in the case of NSISTs, an often unpredictable and delayed response. FDA approval of new biological drugs, like eculizumab, ravulizumab, and efgartigimod have finally changed and updated the therapeutic algorithm of MG, offering new encouraging opportunities in the chronic treatment of MG.

In our article we affirm that prednisone, NSISTs, as well as rituximab, intravenous immunoglobulin (IVIg), and plasma exchange (PE) are not licensed for the treatment of MG by any authority in the world, including FDA and EMA. However, this statement is inaccurate. In fact, for the treatment of severe acute MG exacerbations IVIg (Gamunex® 10%, Grifols Therapeutics, LLC, Research Triangle Park, NC, U.S.A), is licensed in many European countries including Austria, Belgium, Cyprus, Czechia, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Luxembourg, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, and United Kingdom. Approval of Gamunex® 10% has been indeed supported by the strong evidence of its efficacy and safety in the treatment of acute myasthenic exacerbations in various clinical trials [3–5]. Moreover, a randomized trial conducted by Barth et al. also demonstrated that the efficacy of Gamunex® 10% in the treatment of patients with moderate-to-severe MG is comparable to that of plasma exchange [5].

Finally, regarding chronic treatment of MG, we would also like to add for completeness that that tacrolimus is licensed in Japan for the treatment of MG, with a stipulated low dose of 3 mg/day [6].

Declaration of interest

R Mantegazza has received personal compensation for consulting, serving on a scientific advisory board, speaking, travel, or other activities with Alexion Pharmaceuticals, Argenx, BioMarin, Catalyst Pharmaceuticals, Sanofi-Aventis, and UCB. R Mantegazza is also recipient of a grant RF-2016–02364384 of the Italian Ministry of Health entitled ‘Identification of B cell-related biomarkers to predict response to immunosuppressive and B cell targeting therapies in myasthenia gravis.’ F Vanoli received compensation for consulting by Alexion Pharmaceuticals and Argx. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

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Funding

This paper was not funded.