A mutated factor X activatable by thrombin corrects bleedings in vivo in a rabbit model of antibody-induced hemophilia A.

Rendering coagulation factor X sensitive to thrombin was proposed as a strategy that can bypass the need for factor VIII. In this paper, this non-replacement strategy was evaluated in vitro and in vivo in its ability to correct factor VIII but also factor IX, X and XI deficiencies. A novel modified factor X, named Actiten, was generated and produced in the HEK293F cell line. The molecule possesses the required post-translational modifications, partially keeps its ability to be activated by RVV-X, factor VIIa/tissue factor, factor VIIIa/factor IXa and acquires the ability to be activated by thrombin. The potency of the molecule was evaluated in respective deficient plasmas or hemophilia A plasmas, for some with inhibitors. Actiten corrects dose dependently all the assayed deficient plasmas. It is able to normalize the thrombin generation at 20 µg/mL showing however an increased lagtime. It was then assayed in a rabbit antibody-induced model of hemophilia A where, in contrast to recombinant factor X wild-type, it normalized the bleeding time and the loss of hemoglobin. No sign of thrombogenicity was observed and the generation of activated factor X was controlled by the anticoagulation pathway in all performed coagulation assays. This data indicates that Actiten may be considered as a possible non replacement factor to treat hemophilia's with the advantage of being a zymogen correcting bleedings only when needed.

Viral clearance capacity by continuous Protein A chromatography step using Sequential MultiColumn Chromatography.

In response to the strong demand of biological protein therapeutics, such as monoclonal antibodies (MAbs), continuous downstream process was developed to deliver these molecules while maintaining desired product consistency and quality attributes, and providing manufacturing efficiency and flexibility. Viral safety is a critical quality attribute for biopharmaceuticals, such as MAbs. Evaluation of the viral clearance by the downstream process is a key component of risk mitigation. Protein A chromatography is typically used as an initial capture step for MAbs and efficient for the removal of process-related impurities like Host Cell Proteins (HCP). This step can also contribute to the clearance of potential viral contaminants. Murine Minute Virus (MMV)-spiking experiments were performed at small scale to investigate the impact on the viral clearance efficiency of the way the Protein A chromatography step is carried out, whether in batch or multicolumn mode. Protein A chromatography step using Novasep Sequential MultiColumn Chromatography (SMCC) technology demonstrated no statistical difference in the viral reduction with reduction factor (RF) of 3.7 log10 (vs. RF of 3.8 log10 for batch). The experiments showed also similar viral distribution over the purification cycles and columns. Data confirmed that the viral clearance capacity by the continuous Protein A chromatography step using SMCC technology is maintained and efficient.

DNA aptamer affinity ligands for highly selective purification of human plasma-related proteins from multiple sources.

Nucleic acid aptamers are promising ligands for analytical and preparative-scale affinity chromatography applications. However, a full industrial exploitation requires that aptamer-grafted chromatography media provide a number of high technical standards that remained largely untested. Ideally, they should exhibit relatively high binding capacity associated to a very high degree of specificity. In addition, they must be highly resistant to harsh cleaning/sanitization conditions, as well as to prolonged and repeated exposure to biological environment. Here, we present practical examples of aptamer affinity chromatography for the purification of three human therapeutic proteins from various sources: Factor VII, Factor H and Factor IX. In a single chromatographic step, three DNA aptamer ligands enabled the efficient purification of their target protein, with an unprecedented degree of selectivity (from 0.5% to 98% of purity in one step). Furthermore, these aptamers demonstrated a high stability under harsh sanitization conditions (100h soaking in 1M NaOH). These results pave the way toward a wider adoption of aptamer-based affinity ligands in the industrial-scale purification of not only plasma-derived proteins but also of any other protein in general.