PMID: 11916075Mar 28, 2002Paper

Recombinant factor IX recovery and inhibitor safety: a Canadian post-licensure surveillance study

Thrombosis and Haemostasis
Man-Chiu PoonMary-Frances Scully

Abstract

As part of the Canadian post-licensure surveillance on the safety of recombinant factor IX (rFIX. BeneFIX), factor IX recovery and inhibitor development were studied. The recovery following rFIX infusion in 126 patients (mean = 0.77, median 0.72, range 0.36-1.85, 95% CI of mean 0.74-0.81, expressed as FIX activity increase in U/dL per IU FIX concentrate/kg body weight infused) was significantly lower than that following the last plasma-derived factor IX (pdFIX) infusion in 74 patients (mean 1.05, median 1.00, range 0.37-2.29, 95% CI of mean 0.99-0.97). The recovery for rFIX for patients aged < or =15 years (n = 41, mean recovery 0.64) and that for patients aged >15 years (n = 85, mean 0.84) was each significantly lower than that for pdFIX (aged < or =15 years: n = 21, mean recovery 0.91; aged >15 years: n = 53, mean recovery 1.10). For both rFIX and pdFIX concentrates, the recovery was lower in patients < or =15 years of age compared to those > 15 years of age. Similar data and conclusions were obtained on 66 patients with paired recovery data from rFIX and pdFIX. Overall, our data are similar to those obtained in formal clinical trials. Two of 244 patients treated with rFIX for up to 5 years have developed de novo inhibitors a...Continue Reading