Table 1.
The introduction of different partners in the fusion proteins production [137].
| Partner Type | Marketed Examples | The Effects of the Partner | |
|---|---|---|---|
| Non-peptide partners | Fc | Enbrel®, Eloctate® and Alprolix® (FDA approved). | Enlargement to a size greater than 70 kDa (the critical size to escape renal excretion). |
| Albumin | Tanzeum® (FDA approved). | Increases blood circulation | |
| Transferrin | - | Improve oral administration, no FDA-approved cases, | |
| Carboxyl terminal peptide | Elonva® (produced by Merck and Co., Rahway, NJ, USA, but not FDA approved). LagovaTM (in phase 3 clinical trials). | 31 residues with four O-glycosylation sites | |
| Recombinant polypeptide partners | XTEN | - | Increases blood circulation |
| Elastin-like polypeptides | GlymeraTM, VasomeraTM | Contains V-P-G-x-G, the sequence where x is any residue except proline. | |
| Proline-alanine-serine | XL-Protein GmbH (preclinical state). |
The repetition of Pro, Ala and Ser residues in 100–200 copies. Delaying the renal clearance | |
| Glycine-Serine rich peptides | - | As a linker and a partner for medicinal peptides |
Abbreviations: FDA: food and drug administration, Fc: crystallizable fragment, Tf: transferrin, ELP: Elastin-like polypeptides.