Selective immunosuppressant tofacitinib in a child with multiple epiphyseal dysplasia associated with osteoarthritic changes: a case report

Multiple epiphyseal dysplasia is a group of musculoskeletal disorders characterized by genetic heterogeneity in both inheritance patterns and clinical manifestations. One of the most frequent and unfavorable outcomes of this dysplasia is hip osteoarthritis with displacement of the femoral head. Clinical and instrumental manifestations of osteoarthritis in children with multiple epiphyseal dysplasia may often mimic juvenile idiopathic arthritis. Nonsteroidal anti-inflammatory drugs are considered to be pathogenetically justified; however, their efficacy is not always sufficient. The impact of immunosuppressive therapy on the course of osteoarthritis in children with multiple epiphyseal dysplasia has not been previously studied. This article presents a clinical case of successful use of the anti-inflammatory drug tofacitinib, a selective immunosuppressant, in an 11-year-old child with type 4 multiple epiphyseal dysplasia. The disease course was complicated by osteoarthritis and displacement of the right femoral head. No evidence supporting juvenile idiopathic arthritis was identified. Long-term therapy with nonsteroidal anti-inflammatory drugs failed to produce the desired effect. In combination with mechanotherapy, tofacitinib (a Janus kinase inhibitor) 10 mg/day in two divided doses resulted in the resolution of osteoarthritic manifestations and prevention of progression of femoral head displacement. Janus kinase inhibitors are well-known as targeted synthetic disease-modifying antirheumatic drugs. These inhibitors are comparable in efficacy to traditional genetically engineered biological agents used to treat juvenile idiopathic arthritis. Their mechanism of action is based on selective inhibition of intracellular signaling pathways of proinflammatory cytokines. The experience of using selective Janus kinase inhibitors in rheumatology may justify their application in children with skeletal dysplasias complicated by osteoarthritic changes. Type 4 multiple epiphyseal dysplasia is a skeletal dysplasia that inevitably leads to hip osteoarthritis and femoral head displacement. The use of Janus kinase inhibitors in children with this dysplasia accompanied by osteoarthritic manifestations may therefore be justified and highly promising.