Lei-Ting Tony Tam

Rationale-Based Engineering of a Potent Long-Acting FGF21 Analog for the Treatment of Type 2 Diabetes.

Fibroblast growth factor 21 (FGF21) is a promising drug candidate for the treatment of type 2 diabetes. However, the use of wild type native FGF21 is challenging due to several limitations. Among these are its short half-life, its susceptibility to in vivo proteolytic degradation and its propensity to in vitro aggregation. We here describe a rationale-based protein engineering approach to generate a potent long-acting FGF21 analog with improved resistance to proteolysis and aggregation. A recombinant Fc-FGF21 fusion protein was constructed by fusing the Fc domain of human IgG1 to the N-terminus of human mature FGF21 via a linker peptide. The Fc positioned at the N-terminus was determined to be superior to the C-terminus as the N-terminal Fc fusion retained the βKlotho binding affinity and the in vitro and in vivo potency similar to native FGF21. Two specific point mutations were introduced into FGF21. The leucine to arginine substitution at position 98 (L98R) suppressed FGF21 aggregation at high concentrations and elevated temperatures. The proline to glycine replacement at position 171 (P171G) eliminated a site-specific proteolytic cleavage of FGF21 identified in mice and cynomolgus monkeys. The derived Fc-FGF21(RG) molecule demonstrated a significantly improved circulating half-life while maintaining the in vitro activity similar to that of wild type protein. The half-life of Fc-FGF21(RG) was 11 h in mice and 30 h in monkeys as compared to 1-2 h for native FGF21 or Fc-FGF21 wild type. A single administration of Fc-FGF21(RG) in diabetic mice resulted in a sustained reduction in blood glucose levels and body weight gains up to 5-7 days, whereas the efficacy of FGF21 or Fc-FGF21 lasted only for 1 day. In summary, we engineered a potent and efficacious long-acting FGF21 analog with a favorable pharmaceutical property for potential clinical development.

A NOVEL ANION-EXCHANGE RESIN SUITABLE FOR BOTH DISCOVERY RESEARCH AND CLINICAL MANUFACTURING PURPOSES

Strong ion-exchange protein chromatography is one of the most powerful and most common steps for protein purification in both discovery research and manufacturing. However, the demands on protein purification of early drug discovery and later stage manufacturing are quite different. In order to shorten the time of developing a purification process for new protein drug candidates, there is a need for a strong ion-exchange resin that will be optimum for both stages. This article details a novel anion-exchange resin suitable for research, as well as for clinical manufacturing. In this study, a novel Q resin anion-exchange prototype was evaluated and compared to the GE Healthcare Q Sepharose® Fast Flow (QFF) and Q Sepharose® High Performance (QHP) resins. This study specifically focused on the following: resolution, dynamic binding capacity, flow rate, back pressure, and scale up. The evaluation was performed in both small- and large-scale experiments. From all the comparable data, the prototype resin is adaptable for both discovery research and manufacturing. Its wide-range operation suitability could potentially shorten the time required to develop conventional purification protocols for clinical manufacturing.