P91 Bimekizumab-induced drug reaction with eosinophilia and systemic symptoms syndrome

Abstract Drug reaction with eosinophilia and systemic symptoms syndrome (DRESSs) is a potentially life-threatening drug-induced reaction which can present with cutaneous, haematological and internal organ involvement. It is a T-cell-mediated delayed-type drug hypersensitivity reaction and although the pathogenesis is not yet fully understood, it has been recognized also to have significant genetic associations. Bimekizumab is the first monoclonal antibody to selectively inhibit IL-17F and IL-17A and has been approved for the management of plaque psoriasis and psoriatic arthritis in the UK and EU. We present a case of Bimekizumab-induced DRESS syndrome which, to our knowledge, has not yet been described in the literature. The patient is a 45-year-old male with chronic plaque psoriasis who presented with fevers, tachycardia, erythroderma, generalized oedema and lymphadenopathy 10 days after his first treatment with Bimekizumab. He had previously been established on Adalimumab but was still experiencing persistent flares of psoriasis. Laboratory results revealed eosinophilia, raised inflammatory markers and deranged liver function. Histology showed patchy interface dermatitis and moderate-to-severe perivascular chronic inflammatory infiltrate in the dermis with numerous eosinophils, but no psoriasiform changes. He fulfilled the diagnostic criteria for DRESSs, prompting discontinuation of Bimekizumab, treatment with fluid resuscitation, topical steroids and emollients. This resulted in an improvement in clinical picture and laboratory results over a 4-day hospital admission. However, upon tapering down the topical steroids, there was a worsening of his cutaneous symptoms. He developed a generalized eczematous rash on the trunk and limbs with acral oedema. This was further managed with oral ciclosporin and topical steroids. However, upon tapering down the topical steroids, there was worsening of his cutaneous symptoms. He developed a generalised erythematous scaly rash on trunk and limbs with acral oedema. This was further managed with oral ciclosporin and topical steroids. He was subsequently started on Rinsakizumab for the management of his psoriasis. This is a novel case report which demonstrates DRESSs in the context of Bimekizumab treatment for chronic plaque psoriasis. Generally, symptoms develop following a latency period of 3–8 weeks although studies have described ‘rapid-onset DRESSs’ which occurs <15 days following initiation of the culprit drug, which have primarily included antibiotics and contrast media. In this case, the onset of symptoms was earlier than is typically seen in DRESSs and the case highlights the importance of considering this established biologic as a potential cause of DRESSs in future cases.