P108 Immunotherapy of psoriasis in the context of underlying malignant disease: risk–benefit balance?

Abstract The recently established immunotherapeutic approaches to various malignant tumours have dramatically improved patient survival and tumour responses. Yet, they may result in a number of severe unwanted effects on various organs including the skin, which in fact makes up 20–30% of these side effects. Induction or exacerbation of psoriasis is frequent among these. Interdisciplinary care is needed to efficiently approach both tumour and organ-related side effects. This complex issue may be intensively discussed within local interdisciplinary clinical boards on chronic inflammatory diseases (ICB) and is addressed with this case report. A 67-year-old patient was diagnosed with multifocal metastasing small cell lung cancer (SCLS) of his left upper lung lobe and osseous, hepatic and soft tissue metastases. Radiochemotherapy was initiated with cumulative doses of 34 Gy and four cycles of carboplatin and etoposide as well as atezolizumab (anti-PD-L1), the latter continued for maintenance therapy. After 2 years of treatment, no pathologic lymphnodes nor organ metastases could be found with residual pneumonic condensation in his right lung. After 1 year of immune checkpoint inhibition (ICI) both psoriasis arthritis and skin psoriasis appeared with an initial PASI of 20 and a DLQI of 15 and above. The appropriate treatment within this tumour context was intensively discussed by the local ICB. Four injections of guselkumab were well tolerated, yet without any clinical effect. After 7 months of distinct improvement of both skin and joint symptoms upon bimekizumab, clinical effects waned and the therapy was changed another time to injections of adalimumab. This was well tolerated with slow improvement of skin and joint symptoms. The tumour parameters remained unchanged over time. This case demonstrates the induction of psoriasis and psoriasis arthritis by ICI, the critical risk-benefit balance of immunomodulation for psoriasis in the context of underlying malignant disease and the clinical benefit of interdisciplinary discussion within a board on chronic inflammatory diseases.