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

Abstract

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. 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). 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. The association of lenalidomide and dexamethasone with HDIVIg could improve the treatment of relapsed or severe SM.