Antibody fragments (e.g., Fab and scFv ) are generating increased interest among biopharmaceutical companies as an important class of protein-based biotherapeutics. A number of advantages are offered by antibody fragments including: • Elimination of immunogenicity to the Fc region • Easier penetration into tissues due to their smaller size, improved target access and bio-distribution • Reduced cost to produce via microbial and yeast ...

When I was at Genentech, our team developed the downstream commercial process for Lucentis®, a Fab fragment directed at vascular endothelial growth factor (VEGF) for treatment of age-related macular degeneration. Previous non-clinical work had shown that the Fab fragment was particularly adept at penetrating the multiple tissue layers of the retina enabling the antibody fragment to reach its ...

While some antibody fragments can be captured using protein A, other strategies are needed for Fab or other fragments that lack an Fc region. Since the fragments usually have different isoelectric points and differ in their hydrophobicity profile, typically there isn’t a constant property to exploit. This usually requires individual process development for each target molecule, exploiting ion ...

When working with full length monoclonal antibodies, there is a great deal of knowledge about the molecules and well defined platform technologies. Antibody fragments are much less predictable and more variable in term of size and PI. Also, due to the smaller size of fragments, it is typically better to use small beads to ensure better selectivity. Clearly the ...

The matrix used to support a chromatography chemistry has a significant impact on performance.  Beads provide a very large surface area which translates into a very high capacity.  This approach delivers high resolution separations and is readily scalable. With resin bead chromatography however, the solute must diffuse into the pores within the beads in order to reach available binding sites.  Membrane ...

As a whole, membranes offer a cost effective alternative to chromatography. The use of anion-exchange membranes operated in a flow through modality is well established for the reduction of DNA and host cell protein contaminates.  Although developing this type of process step appears on the surface to be quite simple ...

  All else being equal, ideal matrix selection (bead-based resins vs. membranes) is highly application dependent. Due to their porous structure, bead-based resins are typically characterized as having high internal surface area, resulting in high binding capacities for molecules able to readily diffuse into the beads. Consequently, bead-based resins are best suited for capacity-limited ...