P54 | A serious case of multiple site muscle damage secondary to the use of immune checkpoint inhibitor of PD-L1

Premises: Immune checkpoint inhibitors (ICIs) are the major advances in cancer therapy in the recent two decades. These drugs eliminate cancer cells by “releasing the brakes” on T cell activation pathway, i.e. enhancing immune surveillance. This modulatory mechanism inevitably leads to pleiotropic immune related adverse events, which include neuromuscular involvement manifesting as myositis, myocarditis and myasthenic syndrome.Description of the Case report: We describe an 84-years-old man affected by urothelial carcinoma with nodal metastasis treated with avelumab, an anti-programmed cell death ligand 1 antibody. The patient was admitted to our department with weakness of neck muscles, anteflexion of the head and the trunk, bilateral palpebral ptosis lasting for about a week. Blood tests showed elevated CK and LDH levels. Acetylcholine receptor antibodies were detected. Despite timely start of pulse intravenous steroids, it was found a further increase of CK values, worsening of diplopia, dysphonia, dysphagia, tetraparesis and respiratory insufficiency. Subsequently, it was found an important elevation of cardiac enzymes associated with third-degree atrioventricular block. A pacemaker was placed. Intravenous immunoglobulin beyond steroid therapy was started. After some days the patient died.Conclusions: Our case report is paradigmatic of how clinicians should familiarize with this new and potentially life- threatening clinical entity and develop relevant algorithms that allow prompt recognition of symptoms as well as timely treatment.