Fusion Protein Technology to Enhance Pharmacological Properties of L-Asparaginases

L-asparaginase (L-ASNase) is a key therapeutic enzyme used in the treatment of acute lymphoblastic leukemia and other hematological malignancies. However, its clinical application is limited by a short plasma half-life, significant toxicity, and immunogenicity. To address these limitations, various strategies have been developed, including conjugation of the enzyme with polyethylene glycol and the use of enzymes from alternative sources with lower immunogenicity. Nevertheless, effective targeting of tumor cells, particularly in solid tumors, remains a major challenge. Protein fusion technology has emerged as a promising approach to improve the pharmacological properties of L-asparaginase by enhancing stability, prolonging circulation time, enabling targeted delivery, and integrating multiple functional domains into a single construct, thereby addressing several limitations simultaneously. This review analyzes current strategies for the design of L-asparaginase-based fusion proteins, including the fusion of protein domains to improve pharmacokinetics and the fusion of targeting peptides or proteins to enhance local cytotoxicity. A comparative analysis indicates that elastin-like peptide (ELP)-based constructs primarily enhance the half-life of L-ASNase, whereas albumin-binding domain (ABD)- and heparin-binding domain (HBD)-based fusions provide more pronounced improvements in both half-life extension and in vivo efficacy. However, described strategies require further validation to ensure enhanced selectivity. Overall, fusion protein technology represents a promising avenue for the development of next-generation L-asparaginase therapeutics.