Plasma cell‐directed therapies induce profound clinical and durable responses in patients with severe or relapsed/refractory scleromyxedema

Background Scleromyxedema (SM) is a rare skin disorder related to monoclonal gammopathy. High dose intravenous immunoglobulins (HDIVIg) are usually used as a frontline therapy with initial efficacy. However, some patients evolve with relapse, refractory state or severe extra‐cutaneous complications such as dermato‐neuro syndrome (DNS) or cardiac involvement. The objective of the study is to evaluate the use of anti‐plasma cell treatment in these patients in order to obtain a deep and durable dermatological and haematological response. Methods We report here eight patients treated with HDIVIg together with anti‐plasma cell therapy including: lenalidomide and dexamethasone ( n = 5); bortezomib, cyclophosphamide and dexamethasone ( n = 1); daratumumab, lenalidomide and dexamethasone ( n = 2). Results Combination of HDIVIg with a treatment targeting the monoclonal component led to a high level of haematological remission and drastically improved skin response with an acceptable safety profile in all patients. Moreover, HDIVIg was reduced and stopped in 4 of the 7 patients who achieved complete remission. Conclusions The association of lenalidomide and dexamethasone with HDIVIg could improve the treatment of relapsed or severe SM.