A cross‐over pharmacokinetic and thrombogenicity study of a prothrombin complex concentrate and a purified factor IX concentrate

A prospective cross-over study was carried out on 19 patients with haemophilia B. comparing the pharmacokinetics of a purified factor IX concentrate prepared by metal chelate affinity chromatography (9MC) with a conventional three-factor prothrombin complex concentrate (9A). The highly purified factor IX concentrate was shown to have a half-life comparable to the PCC; the in vivo recovery of the purified concentrate was significantly greater than that of the complex (P < 0.01). The 20% change in the value of the International Standard for Factor IX Concentrate, introduced in 1988, might have been expected to lower the recovery values. However, the in vivo recovery for both concentrates was somewhat higher than reported previously, particularly in the older literature. In nine patients, serial assays for fibrinopeptide A, prothrombin fragment F1+2 and thrombin-antithrombin complexes (TAT) were performed to assess the potential thrombogenicity of the two concentrates. Evidence was obtained that there was significantly less activation of coagulation following administration of purified factor IX (9MC), as compared to the activation that occurred after the PCC.