F8 and hemophilia: Longitudinal antibody data from the Hemophilia Inhibitor PUP Study (HIPS; www.clinicaltrials.gov, #NCT01652027) revealed four subgroups of patients who developed distinct signatures of FVIII inhibitors and FVIII-binding antibodies in response to the first 50 exposure days (ED) to a single recombinant FVIII product [11].