Sobi.BIVV001-003 is an open-label, 2-period, fixed sequence study for intra-participant comparison of the PK profiles of efanesoctocog alfa and the extended half-life rFVIII products damactocog alfa pegol or turoctocog alfa pegol after a single i.v. injection in previously treated males, 18-65 years of age, with severe haemophilia A. Participants who are receiving treatment with damoctocog alfa pegol (n\ 12) or turoctocog alfa pegol (n\ 12) will be enrolled in the study. The study will start with a screening period (up to 28 days), including a wash-out period prior to start of the actual study period. During the the first visit, a single dose of damactocog alfa pegol or turoctocog alfa pegol (corresponding to the participant's pre-study treatment) will be administered. A PK sampling period will follow over 7 visits. Following completion of the PK sampling of the original treatment regimen, the patients will be given a single dose of efanesoctocog alfa at visit 8, after which a new PK sampling period will follow (visit 8-15). The primary objective for the study is to compare the half-life of efanesoctocog alfa with that of the two comparator drugs after a single iv. injections. Secondary objectives include comparison of area under the curve for efanesoctocog alfa vs. the two comparator drugs, characterization of PK parameters for all three drugs as well as well as to evaluate safety and tolerability of a single iv. injection of efanesoctocog alfa.