Pharmacokinetic Properties of 2nd-Generation Fibroblast Growth Factor-1 Mutants for Therapeutic Application

Abstract

Fibroblast growth factor-1 (FGF-1) is an angiogenic factor with therapeutic potential for the treatment of ischemic disease. FGF-1 has low intrinsic thermostability and is characteristically formulated with heparin as a stabilizing agent. Heparin, however, adds a number of undesirable properties that negatively impact safety and cost. Mutations that increase the thermostability of FGF-1 may obviate the need for heparin in formulation and may prove to be useful “2nd-generation” forms for therapeutic use. We report a pharmacokinetic (PK) study in rabbits of human FGF-1 in the presence and absence of heparin, as well as three mutant forms having differential effects upon thermostability, buried reactive thiols, and heparin affinity. The results support the hypothesis that heparan sulfate proteoglycan (HSPG) in the vasculature of liver, kidney and spleen serves as the principle peripheral compartment in the distribution kinetics. The addition of heparin to FGF-1 is shown to increase endocrine-like properties of distribution. Mutant forms of FGF-1 that enhance thermostability or eliminate buried reactive thiols demonstrate a shorter distribution half-life, a longer elimination half-life, and a longer mean residence time (MRT) in comparison to wild-type FGF-1. The results show how such mutations can produce useful 2nd-generation forms with tailored PK profiles for specific therapeutic application.

Reprogramming the specificity of sortase enzymes

“…To test whether the combined use of reprogrammed sortases can overcome these limitations, we attempted to synthesize dual N-and C-terminally functionalized proteins of biomedical interest. Fibroblast growth factor 1 (FGF1) is currently being evaluated for the treatment of ischemic diseases but its efficacy is limited by low in vivo stability (25) and has recently been identified as a potential therapeutic agent for the treatment of type-2 diabetes (26). Fibroblast growth factor 2 (FGF2) is an angiogenic factor that has been investigated previously for use in wound healing (27), but its translation into the clinic has also been limited by poor biostability (28).…”

Partnering with Science: New Hope for the Effective Treatment of Type 2 Diabetes

“…We have a number of variants of FGF-1 that are substantially stabilized. We also performed a pharmacokinetic study of FGF-1 in 2012 that showed how to design variants with significantly increased mean residence time in the body [7]. Additionally, from a commercialization standpoint, FGF-1 is in the public domain and cannot be patented.…”

Probing structurally altered and aggregated states of therapeutically relevant proteins using GroEL coupled to bio‐layer interferometry

“…29 We tested FGF-1 that was incubated either at ambient temperature or at 40 C for 5 min both with and without heparin [ Fig. 3(B)], and observed a significantly diminished binding of FGF-1 to the GroEL loaded biosensor in the presence of heparin.…”