A case of new‐onset antibody‐positive myasthenia gravis in a patient treated with pembrolizumab for melanoma

Immune checkpoint inhibitors in the onset of myasthenia gravis with hyperCKemia

“…The patient had positive test results for anti‐AChR and anti‐striational antibodies, which are associated with the onset of MG and myositis/myocarditis, respectively. One case report of ICI‐induced MG without hyperCKemia was negative for anti‐striational antibodies . In contrast, Bielen reported anti‐striational antibody‐positive severe polymyositis after combination therapy with ipilimumab and nivolumab .…”

Refractory myasthenia gravis exacerbation triggered By pembrolizumab

“…Thus, blockade of PD‐1 results in T‐cell dysregulation, a likely pathogenic mechanism for triggering autoimmune conditions such as MG . There are 9 previously reported cases of MG triggered by pembrolizumab, 2 of which were fatal . There are 2 other reports of fatal MG associated with other immune checkpoint inhibitors, 1 following cotreatment with nivolumab and ipilimumab and another following nivolumab, although management of myasthenic crisis was declined in this case .…”

Pembrolizumab‐induced myasthenia gravis with myositis in a patient with lung cancer

“…Of these, nine cases were new‐onset MG , and four cases were exacerbations of pre‐existing MG . Ten cases were of metastatic melanoma , and the remaining three cases were of thymic cancer , uterine carcinosarcoma , and lung squamous cell cancer (our case), respectively. Only five of these cases presented CPK elevation (reported as 10,386 IU/L, 4361 IU/L [our case], 2125 IU/L, 1200 IU/L, and “slightly elevated”).…”