THE FEASIBILITY OF USING CONCENTRATES CONTAINING FACTOR-IX FOR CONTINUOUS-INFUSION

We have investigated the feasibility of continuous infusion of undiluted factor IX (FIX) over several days using minipumps. The stabilities of seven different reconstituted FIX products were substantially better than those declared by the manufacturers. Several concentrates maintained factor activities above 80% of baseline for the entire period of 4 weeks at 4-8 degrees C as did one product at 20-23 degrees C. At 37 degrees C the latter concentrate was stable for at least 1 week. The stability seemed to correlate with the purity of the product. Analysis of two prothrombin complex concentrates by gel electrophoresis demonstrated degradation of prothrombin to prethrombin-1 and fragment 1 at 37 degrees C and in one of the concentrates also at 20-23 degrees C. In two FIX concentrates the corresponding analysis did not reveal any degradation. Four patients were treated with continuous infusion with a pure FIX concentrate (Mononine(TM), Armour) after surgery or for serious haemorrhage (two each) with good haemostatic effect, an initial progressive decrease of the FIX clearance, and no side-effects. Continuous infusion with FIX, using a minipump and undiluted reconstituted factor, is therefore feasible and effective, and can be conveniently prepared for several days at a time. Pure FIX products are more stable and probably safer for this purpose