Abstract
With the increasing availability of human plasma this source was used to substitute for the production of factor XIII concentrate from placenta. Prior to changing the source material, the virus safety in accordance with the Committee for Proprietary Medicinal Products (CPMP) guidelines and the half-life were investigated.
Concerning the virus safety, the following cumulative log 10 clearance factors were obtained: human immunodeficiency virus (HIV) ≥ 18.9, herpes simplex virus (HSV-1) ≥ 21.5, polio ≥ 19.1, bovine viral diarrhea virus (BVDV) ≥ 13.3. Half-life studies of factor XIII from plasma in comparison with factor XIII from placenta were done in rabbits by determination of the antigen and in patients with congenital factor XIII deficiency by determination of the activity and antigen.
In rabbits, the terminal half-life of the antigen was 78.2 hours for factor XIII from placenta and 87.0 hours for factor XIII from plasma. In patients the half-lives were similar: 9.2 days for activity and antigen of factor XIII from plasma and 8.5 days (activity) versus 9.4 days (antigen) for the placenta-derived factor XIII. Some further clinical studies with factor XIII concentrates are also reviewed.
Newer developments concerning recombinant factor XIII, its expression, characterization, and properties are summarized. Concerning the physicochemical data, the behavior in plasma was characterized by the formation of high-molecular-weight complexes, and first in vivo results, the recombinant factor XIII product was comparable to the naturally occurring material.
Key words:
Factor XIII from plasma - recombinant factor XIII - virus safety - half-life - clinical results
