Novel Hepatitis B Virus Capsid Assembly Modulator Induces Potent Antiviral Responses In Vitro and in Humanized Mice

Abstract

Hepatitis B virus (HBV) affects an estimated 250 million chronic carriers worldwide. Though several vaccines exist, they are ineffective for those already infected. HBV persists due to the formation of covalently closed circular DNA (cccDNA)—the viral minichromosome—in the nucleus of hepatocytes. Current nucleoside analogs and interferon therapies rarely clear cccDNA, requiring lifelong treatment. Our group identified GLP-26, a novel glyoxamide derivative that alters HBV nucleocapsid assembly and prevents viral DNA replication. GLP-26 exhibited single-digit nanomolar anti-HBV activity, inhibition of HBV e antigen (HBeAg) secretion, and reduced cccDNA amplification, in addition to showing a promising preclinical profile. Strikingly, long term combination treatment with entecavir in a humanized mouse model induced a decrease in viral loads and viral antigens that was sustained for up to 12 weeks after treatment cessation.

Studies on the Efficacy, Potential Cardiotoxicity and Monkey Pharmacokinetics of GLP-26 as a Potent Hepatitis B Virus Capsid Assembly Modulator

“…GLP-26 had considerable antiviral activity when combined with ETV ( Figure 1 C). Although the physiology of AD38 tumor xenografts differ from that of infected human liver, the effect of GLP-26 and ETV on serum HBV titers observed with the tumor xenograft model resembled those observed in our previous study in a humanized mouse model of HBV infection [ 9 ].…”

“…Results revealed 86.7% binding in monkey and 89.5% in human plasma, respectively. For comparison, 0.8% of emtricitabine (negative control) and 97.9% of lopinavir (positive control) were bound in human plasma, and 17.9% was bound in 2% FBS (used to measure potency in vitro) [ 9 ]., These binding data were used to estimate the in vivo potency from the in vitro EC 50 (3 nM~1.1 ng/mL) and EC 90 (30 nM~11 ng/mL) using the equation: in vivo potency = in vitro potency × % bound in plasma/% bound in 2% FBS. The normalized EC 50 and EC 90 were superimposed on Figure 5 A,B.…”

“…GLP-26 (molecular weight = 373.4 g/mol), BMS-986094 and emtricitabine (FTC) were prepared in house according to published procedures [ 9 ]. The purity of these compounds was greater than 98% as determined by high-performance liquid chromatography (HPLC) and NMR methods.…”

“…Our group recently published on GLP-26, a novel non-toxic glyoxamide derivative which modulates HBV capsid assembly with low nanomolar antiviral activity, resulting in reduced cccDNA and HBV antigen levels in vitro [ 9 ]. Strikingly, in a humanized HBV mouse model, combination treatment with entecavir (ETV) decreased viral loads and viral antigens (such as HBeAg and HBsAg) with sustained virology response (SVR) for up to 12 weeks after treatment cessation [ 9 ]. Based on these results, further in vivo characterization and preclinical development were warranted.…”

“…Based on these results, further in vivo characterization and preclinical development were warranted. We examined the anti-HBV efficacy of GLP-26 and ETV in nude mice supporting the growth of subcutaneous human hepatoblastoma cells replicating HBV (AD38 cells) [ 10 ] previously established by Feitelson et al and compared the results with those from the humanized mouse study [ 9 , 11 ]. In this model, nude mice bearing AD38 tumor xenografts stably transfected with HBV and under the control of a tetracycline (TET) operon were used [ 11 , 12 ].…”