title: Exacerbation of myasthenia gravis in a patient with melanoma treated with pembrolizumab.
abstract: While anticancer immunotherapies have traditionally focused on activation of the immune system, there is recent interest in disinhibition of the natural antitumor immune response by targeting immune checkpoints such as cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) and programmed death-1 (PD-1). One humanized monoclonal antibody against PD-1, pembrolizumab, was recently approved for treatment of metastatic malignant melanoma.
  
  
  
  We report exacerbation of myasthenia gravis (MG) after treatment with pembrolizumab and provide a brief literature review.
  
  
  
  We describe a 75-year-old man with stable MG who experienced myasthenic crisis in the setting of pembrolizumab treatment. A concurrent azathioprine taper was a possible although unlikely contributor given the short time interval between taper and exacerbation.
  
  
  
  As long-term data become available regarding the adverse immune effects of novel checkpoint inhibitors, clinicians should be mindful of their risks/benefits and of possible autoimmune disease exacerbation. Muscle Nerve 54: 157-161, 2016.
authors.affiliation: Yale University School of Medicine, Department of Neurology, Division of Neuromuscular Medicine, PO Box 208018, New Haven, Connecticut, 06520, USA.
authors.forename: K H Vincent
authors.initials: KH
authors.lastname: Lau
authors.affiliation: Yale University School of Medicine, Department of Neurology, Division of Neuromuscular Medicine, PO Box 208018, New Haven, Connecticut, 06520, USA.
authors.forename: Aditya
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Yale University School of Medicine, Department of Neurology, Division of Neuromuscular Medicine, PO Box 208018, New Haven, Connecticut, 06520, USA.
authors.forename: Irene Hwa
authors.initials: IH
authors.lastname: Yang
authors.affiliation: Yale University School of Medicine, Department of Neurology, Division of Neuromuscular Medicine, PO Box 208018, New Haven, Connecticut, 06520, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Nowak
mesh_terms: D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects*; D000970:Antineoplastic Agents / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008545:Melanoma / Q000150:complications* / Q000188:drug therapy*; D009157:Myasthenia Gravis / Q000139:chemically induced* / Q000150:complications*
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; C582435:pembrolizumab
keywords: anti-PD1; autoimmune adverse effect; immune checkpoint inhibitor; melanoma; myasthenia gravis; pembrolizumab