Mean factor IX activity versus time at months 0, 6, 12, 18, and 24.

PK parameters were estimated for 56 patients at baseline. Fifty-three patients had PK parameters estimated at 6 months, 51 patients at 12 months, and 48 patients at 18 and 24 months. The data from one patient (months 12, 18, 24) were excluded after inhibitor development.