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Updated: Jul 3, 2025

Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
A case of coagulation factor V inhibitor induced by immune checkpoint inhibitor therapy
Yuki Haruta1, Masanori Azuma1, Toshikatsu Sado1
1Department of Respiratory Medicine Osaka Saiseikai Nakatsu Hospital Osaka Japan.
Abstract:
A 73-year-old woman with lung adenocarcinoma (cT4N3M1a: Stage IVA) was treated with atezolizumab as the eighth line of therapy. Four weeks after the fourth dose of atezolizumab, the prothrombin time (PT) and activated thromboplastin time (APTT) were prolonged. Coagulation factor V (FV) activity was decreased, and FV inhibitors were observed. There was no history of PT or APTT prolongation or bleeding before the use of atezolizumab. Atezolizumab-induced coagulation FV inhibitor was diagnosed. After 2 weeks, the PT and APTT spontaneously normalized. FV activity improved and the FV inhibitors disappeared after 6 and 9 weeks, respectively.
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