Abstract Introduction Pembrolizumab is an immune check point inhibitor binds to programmed cell death-1 (PD-1) on T-cells to block PD-1 ligands (PD-L1 and PD-L2). Pembrolizumab is used for the treatment of various cancers and is associated with neurological adverse effects (6% with PD1 inhibitors) (1). Myasthenia gravis is one of rare complications of Pembrolizumab (2, 3). Case Report This is a 74-year-old male with history of hypertension and recently diagnosed stage IIb pT3bN0M0 melanoma (excision of left superior upper back nodular growth) was started on IV Pembrolizumab. Patient started having diffuse body aches, drooping of both upper eyelids, difficulty with reading and difficulty in swallowing after few weeks of the first dose of IV Pembrolizumab, so was referred for the admission. Vital signs were normal. Examination showed bilateral ptosis and muscular strength 4/5 in all extremities. Laboratory work up showed elevated liver enzymes and creatine kinase (AST 879 U/L, ALT 609 U/L and CK 9736 U/L). CT head and MRI brain did not show any acute pathology. Patient was started on IV fluids, pyridostigmine and IV immunoglobulin. Acetylcholine receptor binding, blocking, modulating antibodies and muscle specific kinase antibodies were negative but striated muscle antibody was positive. Patient clinically improved over time, so was discharged on pyridostigmine. Patient returned to the hospital after four weeks of the discharge with difficulty in swallowing and difficulty in breathing, so was admitted to the intensive care unit for close monitoring (had normal negative inspiratory force and vital capacity). Patient was started on IV dexamethasone and IV pyridostigmine. CT chest did not show thymic mass. Neurology recommended plasmapheresis. Patient clinically improved in respect to difficulty breathing after completing plasmapheresis sessions but continued to have difficulty in swallowing, so received percutaneous gastrostomy tube. Patient was transferred out of ICU and subsequently discharged. Discussion Very rare and serious complication of immune check point inhibitor. References: 1. Puzanov I, Diab A, Abdallah K, et al. Managing toxicities associated with immune checkpoint inhibitors: consensus recommendations from the Society for Immunotherapy of Cancer (SITC) Toxicity Management Working Group. J Immunother Cancer 2017; 5:95. 2. Safa H, Johnson DH, Trinh VA, et al. Immune checkpoint inhibitor related myasthenia gravis: single center experience and systematic review of the literature. J Immunother Cancer 2019; 7:319. 3. Naidoo J, Page DB, Li BT, et al. Toxicities of the anti-PD-1 and anti-PD-L1 immune checkpoint antibodies. Ann Oncol 2015; 26:2375. This abstract is funded by: None
Loya et al. (Fri,) studied this question.