Transarterial periarticular embolization (TAPE) in checkpoint-inhibitor-associated arthritis—a novel treatment strategy

Dear Editor, The use of immune checkpoint inhibitor (ICI) immunotherapy to treat malignancies can lead to immune-related adverse events (irAEs), such as arthritis. It has been observed that the immunosuppressive treatment of these irAEs can lead to a reduction in the efficacy of the ICI. This may subsequently contribute to tumour progression. Transarterial periarticular embolization (TAPE) has become a minimally invasive procedure for the treatment of osteoarthritis of the knee and early studies describe benefits in terms of pain and improved function (for detailed information regarding TAPE, see Supplementary Data S1, available at Rheumatology online) [1–3]. The aim of this project is to evaluate the clinical feasibility of TAPE as a novel approach for the treatment of ICI-associated arthritis. A 47-year-old woman was diagnosed with stage IV adenocarcinoma of the ascending colon (RAS wild type, microsatellite instability-high) with peritoneal metastases in February 2013 (for detailed baseline characteristics, see Supplementary Table S1, available at Rheumatology online and for detailed information regarding tumour stage, see Supplementary Data S2, available at Rheumatology online). Based on tumour progression, the patient received immunotherapy with the ICI nivolumab [monoclonal body that inhibits the programmed death-1 (PD-1) receptor]. After three cycles, the patient presented with stiffness, swelling and pain of the left knee and was referred to our hospital’s rheumatology department for further assessment (Fig. 1A-1). Blood analysis, such as rheumatoid factor and anti-citrullinated protein antibodies, were negative. Ultrasound (Fig. 1B-1) and MRI of the left knee revealed a hypervascularized synovitis (Fig. 1C-1), establishing the diagnosis of an ICI-associated arthritis of the left knee.