Hepatitis delta virus: From infection to new therapeutic strategies

Table 1 Established and undergoing drugs in the management of hepatitis delta virus chronic hepatitis

Molecule	Drug	Mechanism of action	Drug administration	Duration of therapy	Current therapy/clinical trials	Most frequent side effects
Interferon	Pegylated Interferon-α	Immunomodulatory and antiviral activity	Subcutaneously Weekly	Recommended at least 48 wk	Established Therapy; Long-term follow up, after discontinuation of therapy, available	Flu-like symptoms; Headache; Myalgias; Arthralgias; Anemia; Leukopenia; Thrombocytopenia
Myristoylated Lipopeptide	Myrcludex B; Bulevirtide	Interference with HDV viral entry through NTCP	SubcutaneouslyDaily; ± Peg-IFN; ± Tenofovir	At present maximum 48 wk	Ongoing Phase 3 clinical trial	Thromocytopenia; Neutropenia; Lymphopenia; Eosinophilia; Bile Acids elevation
Farnesyl-transferase Inhibitor	Lonafarnib	Inhibition of HDV viral assembly	Orally; Daily; ± Ritonavir; ± Peg- IFN	At present maximum 48 wk	Ongoing Phase 3 clinical trial	Nausea; Diarrhea; Loss of appetite; Weight loss; Abdominal Bloating Increased ALT levels
Phosphorothioate nucleic acid polymer	Rep 2139	Post-entry inhibition of HBsAg secretion; Possible interference with viral entry	Intravenously; Weekly; ± Peg-IFN	At present maximum 30 wk	Phase 2 clinical trial	Thromocytopenia; Neutropenia; Anaemia; Increased ALT levels

HDV: Hepatitis delta virus; NTCP: Sodium tauro-cholate cotransporting polypeptide; Peg-IFN: Pegylated interferon; ALT: Alanine aminotransferase; HBsAg: Hepatitis B surface antigen.