HESylation is an innovative technology based on the extensive expertise of Fresenius Kabi in the field of hydroxyethyl starch (HES), the world's largest producer of HES. HES is a modified natural polymer that has been widely used in clinical practice for decades as a plasma volume expander. Consequently, it has an impressive safety record.

HESylation represents the technology of coupling drug substances with HES derivatives in order to modify drug characteristics, such as pharmacokinetics or water solubility. This also includes the prolongation of protein plasma circulation via an increased stability of the molecule and a reduced renal clearance, resulting in an increased biological activity. In addition, the immunogenicity or allergenicity might be reduced. By varying different parameters, such as the molecular weight of HES, a wide range of HES conjugates can be customized.

At present, the most important application area for HESylation is clearly biopharmaceuticals, i.e. protein drugs. Nevertheless, there is a strong potential for HESylation to improve the profile of small molecule drugs.

Fresenius Kabi has a broad portfolio of patents and patent applications covering coupling chemistry, special linkers and HESylated substances on a target-by-target basis. Detailed information available on request.

Fresenius Kabi offers different kinds of partnerships including a specific technology transfer and supply of HES derivatives (one-stop-shop):

- Feasibility studies to evaluate the technology with different targets.

- Development collaborations to improve the efficacy or safety profile of protein/peptide drugs as well as small molecule drugs.

- Exclusive licensing of the HESylation technology for certain targets.

- Supply of customized HES derivatives and HESylated targets.