Background. Enzyme replacement drugs for treatment of mucopolysaccharidosis type II (MPS II) do not penetrate the blood-brain barrier, significantly reducing their efficacy in patients with neuropathic form. Verenafusp alfa (Clotilia®) is a recombinant fusion protein of iduronate-2-sulfatase and a monoclonal antibody Fab fragment to human insulin receptor for distribution of the enzyme into brain.
Aim. To evaluate safety, tolerability, and pharmacokinetic parameters of verenafusp alfa after single intravenous administration of escalating doses in healthy volunteers.
Materials and methods. This open-label, multicohort study included 20 healthy male volunteers aged 18 to 47 years (26.1±7.8 years). Verenafusp alfa was administered intravenously for 3 hours at single doses of 0.3 mg/kg (n=1), 0.5 mg/kg (n=1), 1 mg/kg (n=6), 2 mg/kg (n=6), and 3 mg/kg (n=6). Safety was assessed based on the incidence of clinical and laboratory adverse events (AEs) and their relationship to the investigational medicinal product. Pharmacokinetic parameters were calculated using a noncompartmental method.
Results. All 20 volunteers completed the study. AEs reported in 6 (30%) volunteers were mild in severity and related to changes in individual laboratory and instrumental test data. One AE (increased bilirubin level) was possibly related to the study drug. Pharmacokinetic analysis demonstrated a dose-dependent increase in maximum concentration (Cmax) from 197.60 (0.3 mg/kg) to 10,225.80 ng/mL (3 mg/kg) and area under the concentration-time curve (AUC) from 38,678.60 to 2,714,067.42 ng×min/mL respectively. The half-life ranged from 86.69 to 213.42 minutes, and clearance lowered with the increasing dose from 7.67 to 1.11 mL/min/kg.
Conclusion. Single intravenous administration of verenafusp alfa at doses ranging from 0.3 to 3 mg/kg demonstrated a favorable safety profile and good tolerability in healthy volunteers. The drug's pharmacokinetics was nonlinear, with a dose-dependent increase in Cmax and AUC with the dose increment. Volume of distribution volume lowered with increase of the dose.