A plasma-derived (pd) product consisting of a mixture of FVIIa and FX (pd-FVIIa/FX), at a protein weight ratio of 1:10, was approved for people with congenital hemophilia with inhibitors and acquired hemophilia in Japan in 2014 [11,12], and clinical trials of on-demand and prophylactic pd-FVIIa/FX have been reported [[13], [14], [15]]. Here, F10 is linked to hemophilia.