Researchers identified clinical differences between immune-related myasthenia gravis (MG), a life-threatening adverse event from the use of immune checkpoint inhibitors, and idiopathic MG, and published their findings in Frontiers of Neurology. They also identified factors to predict immune-related MG prognosis.

“With the increased use of [immune checkpoint inhibitors], the incidence of [neurological adverse events] is growing, among which [immune checkpoint inhibitor]-related MG is causing a high fatality rate,” the authors wrote. “In this study, we report an extensive case series of [immune checkpoint inhibitor]-related MG with detailed clinical features, treatments, and disease outcomes.”

The research team included 6 patients diagnosed with immune-related MG between September 2019 and October 2021, along with 380 patients with idiopathic MG during the same time period as controls. They also conducted a literature review of 40 studies describing 57 patients with cancer and MG who were treated with immune checkpoint inhibitors.

Read more about MG differential diagnosis

Demographic data, baseline characteristics, myocarditis/myositis, and disease severity as measured by the Myasthenia Gravis Foundation of America (MGFA) and quantitative myasthenia gravis score (QMGS) were collected.  

The results showed that the majority of patients with idiopathic MG were younger, had a slower disease course, and fell within MGFA classes 1 and 2 at diagnosis. Those with immune-related MG were more likely to be in MGFA classes 3 and 4 at diagnosis and they also had higher QMGS rates than those with idiopathic MG. Patients with immune-related MG were more likely to experience myocarditis or myositis, a rare occurrence in those with idiopathic MG.

Finally, the team determined that a higher MGFA classification and QMGS rate at diagnosis were predictive of a poor disease outcome. Therefore, given the expected increase in the use of immune checkpoint inhibitors, in cases of suspected immune-related MG, the authors recommend early assessments of MGFA, QMGS rates, and myositis/myocarditis.

Reference

Shi J, Tan Y, Huan Y, et al. Association between clinical factors and result of immune checkpoint inhibitor related myasthenia gravis: a single center experience and systematic review. Front Neurol. Published online April 7, 2022. doi:10.3389/fneur.2022.858628