Hepatitis B Nasal Vaccine for Patients with Refractory Chronic Hepatitis B

It is estimated that more than 240 million people are infected with hepatitis B worldwide, and for that reason it continues to be a major public health problem. Chronic hepatitis B (CHB) infection is considered a major risk factor for serious liver disease such as cirrhosis, hepatocellular carcinoma, and related complications. 

Current antiviral therapies have limited treatment efficacy, requiring long-term continuous and expensive treatments and follow-ups, and definitive viral elimination is not frequent. 

A novel therapeutic option is the vaccine formulation called HeberNasvac that has been tested in preclinical and clinical studies. The product was originally developed as a nasal vaccine for CHB immunotherapy that comprises the hepatitis virus (HBV) surface and core recombinant virus-like particles (VLP). 

HeberNasvac was very immunogenic in mice after intranasal or parenteral administrations inducing high antibody titers, potent proliferative responses and the secretion of gamma interferon by spleen cells. It was also demonstrated to be safe in phase 1 trials in healthy volunteers. Also phase I, II and III clinical trials conducted in Bangladesh demonstrated the safety and efficacy of the vaccine in treatment of naive CHB patients.

Clinical Trial in Cuba

In a phase 1 clinical trial conducted in Cuba, in which 6 patients with CHB infection refractory or with incomplete response to α-IFN, patients were immunized ten times every 2 weeks via nasal spray with 100 micrograms of HBsAg and 100 micrograms of HBcAg.

The clinical efficacy was monitored by assessing the levels of hepatitis B virus DNA, alanine aminotransferase (ALT), HBeAg, and anti-HBeAg seroconversion as well as serology of HBsAg. 

After a 5 year follow up, HBeAG loss was verified in 3 HBeAG+ patients, in 2 cases with seroconversion to anti-HBeAG. Also a reduction to undetectable viral load was observed in 5 out of 6 patients, and in 2 cases HBsAg seroconversion was also detected. 

Although few patients were included in the study, the results are promising and it seems that HeberNasvac may maintain some of the therapeutic effects for a prolonged time, which led to researchers to a transition form a preventive vaccine only, to a therapeutic implication of the biologic. 

Source:

Fernández G, L Sanchez A, Jerez E, et al. Five-year Follow-up of Chronic Hepatitis B Patients Immunized by Nasal Route with the Therapeutic Vaccine HeberNasvac. Euroasian J Hepatogastroenterol. 2018;8(2):133-139. doi:10.5005/jp-journals-10018-1279

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