Jürgen Römisch

Combinatorial peptides directed to inhibitory antibodies against human blood clotting factor VIII.

The development of antibodies against blood clotting factor VIII is a major complication affecting 20-30% of hemophilia A patients receiving replacement with FVIII concentrates. This study investigated generating peptides acting as broadly neutralizing agents to block factor VIII antibodies. These peptides were selected from dual positional scanning decapeptide libraries on cellulose membranes. From this library comprising 6.8 x 10(12) peptides we selected 468 peptides for further screening rounds. Finally we identified two decapeptides with the ability to block 8 out of 10 inhibitory antibodies from sera of patients with FVIII inhibitors demonstrated by competition assays. Sequence alignment of the peptides showed similarity with several domains in the FVIII molecule demonstrating the mimotope nature of the selected peptides. Our results show the efficiency of the combinatorial library approach and show the potential of combinatorial peptides to compete out polyclonal inhibitor IgG from a broad range of patients sera. Combinatorial peptides could be novel and highly effective drug candidates for alternative treatment in patients with factor VIII inhibitors.

Thawing of Pooled, Solvent/Detergent-Treated Plasma octaplasLG®: Validation Studies Using Different Thawing Devices

Background: The aim of this study was to perform validation of the thawing process for solvent/detergent-treated plasma octaplasLG® using different thawing devices. Optimized settings for temperature and thawing time should be defined based on the results of both temperature measurements and extensive biochemical characterization studies. Methods: octaplasLG units were thawed using water bath systems (i.e. MB-13A, QuickThaw® DH4), dry tempering systems (i.e. plasmatherm, SAHARA-III), and microwave oven (i.e. transfusio-therm® 2000). Optimized thawing conditions were defined. Subsequently, using the selected thawing conditions, octaplasLG units were thawed and tested on product release parameters. Results: The fastest thawing was observed for the microwave oven. All octaplasLG units thawed by different devices and optimized thawing conditions were clear and free of solid and gelatinous particles, indicating no protein denaturation or overheating. In addition, no significant differences were found in the coagulation and inhibition activity and hemostatic potency of octaplasLG when thawed by the different devices tested. All parameters after thawing were within the product release specification levels. Conclusion: Our study demonstrated that octaplasLG can be thawed using all above listed devices without any negative influence on the plasma quality, presupposed that optimized settings defined for this plasma product are used.

Biochemical characterization and stability of immune globulin intravenous 10% liquid (Panzyga ® )

Panzyga® is a new glycine-formulated immune globulin intravenous 10% liquid for the treatment of patients suffering from immunodeficiencies and autoimmune diseases. Panzyga® is a high purity, native and functional IgG product with an IgG subclass distribution equivalent to normal plasma. The levels of hemagglutinins and accompanying plasma proteins (including IgA and IgM) are low. Potential procoagulant activity is not detectable. Functional activity of the IgG was demonstrated by opsonophagocytosis and receptor binding assays. Dynamic light scattering measurements and fluorescent dye binding were used to characterize the integrity of the IgG molecule. Panzyga® is stable under refrigerated storage for at least two years regarding all assessed physicochemical and functional parameters; it can also be stored at room temperature for at least twelve months within its total shelf-life.

Biochemical characterization, stability, and pathogen safety of a new fibrinogen concentrate (fibryga®)

Fibryga® is a new lyophilized fibrinogen concentrate for intravenous use for the treatment of congenital fibrinogen deficiency. fibryga® is produced from pooled human plasma and the final product is characterized by high purity, integrity, and pathogen safety. Functional activity of fibrinogen was demonstrated by cross-linking studies and thromboelastometry; integrity of the fibrinogen molecule was demonstrated by size exclusion chromatography and the detection of only trace amounts of activation markers in the final product. Pathogen safety of fibryga® was proved by downscaling studies for the two dedicated pathogen inactivation/removal steps, i.e. solvent detergent treatment and nanofiltration. Fibryga® is stable for at least three years when stored at room temperature. In conclusion, the performed studies demonstrated that fibryga® meets the requirements for a state-of-the-art fibrinogen concentrate, such as a satisfactory activity profile combined with a favorable pathogen safety profile and stability.