Rapid clinical improvement of refractory subacute cutaneous lupus erythematosus with oral TYK2 inhibitor deucravacitinib: a case report

Background: Cutaneous lupus erythematosus (CLE) is a clinically variable chronic relapsing inflammatory dermatosis. Antimalarials and conventional immunosuppressive drugs (e.g. glucocorticosteroids, methotrexate [MTX]; mycophenolate-mofetil [MMF]) are currently the mainstay of therapy for severe cases. Given the Th1-polarized inflammatory pattern with type 1 interferons as key pathogenic drivers, januskinase inhibition might represent another viable option. Case report: A 56-year old female Vietnamese patient first presented in 02/2022 with a history of malar rash and itchy erythematous scaly lesions on her back for two months. Her medication consisted of amlodipine and candesartan for hypertensions and metformin for diabetes (longer than 3 months). Laboratory workup revealed antinuclear antibodies (1:1280), SSA- and SAE1-antibodies. Histology showed interface dermatitis and patchy lymphocytic aggregates. No signs of organ involvement were detected. Underlying malignancy could be excluded. We diagnosed subacute CLE with partly overlapping features of Sjögren’s syndrome. Over the course of 15 months the patient was treated with combinations of hydroxychloroquine (HCQ) and MTX as well as HCQ and MMF. Although she received pulses of medium to high doses of prednisolone, short remissions were followed by disease flares upon tapering. In May 2023, MMF therapy was terminated, we introduced deucravacitinib 6mg p.o. once daily and continued HCQ 200mg twice daily with prednisolone 5mg p.o. once daily. The patient experienced a drastic improvement in spite of higher UV exposure during summer season. Until now, therapy is continued without adverse events. Discussion: Deucravacitinib is a selective allosteric TYK2-inhibitor licensed for psoriasis that interferes with interferon α/β and IL12/23 signalling. It is under clinical investigation for systemic lupus erythematosus (SLE), in a phase 2b clinical trial skin scores improved more often in the interventional arms compared to placebo. Our case report highlights the potential benefit of deucravacitinib for CLE patients, which should be addressed in further studies.