Commercial considerations

Extensive expertise with PEGylated macromolecules has led to the conclusion that no inherent technical or commercial constraints limit the manufacture and scale-up of small-molecule PEGs. The chemistries of these molecules are different (i.e., organic as opposed to aqueous), however, and PEGs must sometimes be built into a small molecule during synthesis. This procedure requires specific expertise. Cost is not expected to significantly affect the commercial feasibility of PEGylated small molecules because costs are well within commercial parameters. Shelf life and stability could actually improve over those of the parent compounds because PEG can be a stabilizing molecule. From a regulatory point of view, the US Food and Drug Administration considers PEG small molecules as new chemical entities (NCEs) subject to the same standards as nonPEGylated NCEs. The technology and molecules can be protected by patents. For example, Nektar has 55 issued patents and 490 applications worldwide that cover polymer structures, polymer linkers, composition of matter, manufacturing, and mechanism and delivery modalities. Thus, patent protection of non-PEGylated drugs is not expected to affect PEGylated drugs' commercial prospects.

Conclusion

Timothy Riley, PhD,* is vice-president of PEGylation research, and Jennifer Riggs-Sauthier is director of science and technology at Nektar Therapeutics, 490 Discovery Dr., Huntsville, AL 35806, tel. 800.457.1806, fax 256.533.4805, triley@nektar.com

*To whom all correspondence should be addressed.

Reference

1. A. Abuchowski et al., "Effect of Covalent Attachment of Polyethylene Glycol on Immunogenicity and Circulating Life of Bovine Liver Catalase," J. Biol. Chem. 252 (11), 3582–3586 (1977).