An elderly patient with metastatic lung adenocarcinoma presented with excessive bruising and persistent oozing several months after treatment with pembrolizumab, an immune checkpoint inhibitor. The cause of this hemostatic deficiency was identified as an inhibitor to factor VIII. Therapy with FEIBA (factor VIII inhibitor bypass activity), corticosteroids and immune gamma globulin resulted in clinically adequate improvement, but incomplete normalization of hemostatic parameters. Durable and complete restoration of aPTT and factor VIII activity occurred after subsequent treatment with rituximab, and supports its use as definitive therapy for acquired hemophilia resulting from the use of immune checkpoint inhibitor monoclonal antibodies.
Key words: acquired hemophilia, pembrolizumab, acquired factor VIII inhibitor, coagulopathy
|
