© 2016 Informa UK Limited, trading as Taylor & Francis Group.Empirical analysis of matched patent application data in the world’s major patent offices has shown considerable variation in patent granting probability and examination duration across different countries. This phenomenon is attributed to institutional misclassifications or patent examiners’ mistakes by some authors. Others argued that cross-country heterogeneity could also be caused by deliberate manipulation of patent examination procedures with the goal to foster native inventors through suppressing foreign patent applicants. To explore whether manipulation exists, this study presents a case study of pharmaceutical patents granted by the US patent office and approved by the US FDA. Especially it focuses on the filing behavior of pharmaceutical companies in Korea, Japan and China. The regression results show that the granting ratio of the previous applications of a foreign company is correlated with the company’s probability of lodging a new patent application, which provides a supplementary evidence of the existence of the manipulated patent examination procedures.