Vaccitech plc has announced positive topline final data from the HBV002 study, a phase 1b/2a clinical trial of VTP-300 in people with chronic hepatitis B (HBV) infection.
Vaccitech is a clinical-stage biopharmaceutical company focused on the development of novel T cell immunotherapeutics to use the immune system to potentially treat and cure chronic infectious diseases, autoimmune diseases and cancer.
The completed trial, which included 55 patients with chronic hepatitis B, supported the generally favorable tolerability profile previously reported with VTP-300, with no incidents of VTP-300-related grade 3 adverse events or product-related serious adverse events following study dosing. VTP-300 was observed to induce meaningful, sustained reductions of hepatitis B surface antigen (HBsAg) in patients with chronic HBV. Declines were most prominent in patients with lower baseline HBsAg. The final results of the immunology assays are currently being analyzed.
“The safety data and HBsAg reductions in the HBV002 study are very encouraging and we look forward to sharing the full data set, including immune responses, at the EASL conference,” said Bill Enright, CEO of Vaccitech.
“Less than 10% of people with chronic HBV reach a functional cure with current therapies. We believe VTP-300 has the potential to be a critical component of functional cure for HBV, potentially eliminating the need for chronic treatment. Our ongoing trials are exploring dosing, including an additional booster, and combination approaches with readouts expected towards the end of the year.”
A phase 2b clinical trial to evaluate timing of low dose nivolumab and additional doses of the MVA boost component of VTP-300 has been initiated in multiple countries within the Asia-Pacific region, with interim data expected in Q4 2023.
In addition, a phase 2a clinical trial, in collaboration with Arbutus Biopharma Corporation, is evaluating the safety, antiviral activity and immunogenicity of VTP-300 administered after Arbutus’ AB-729 in 40 virologically-suppressed chronic HBV patients, with interim data also expected in Q4 2023.
Vaccitech’s VTP-300
VTP-300 is a heterologous immunotherapy candidate consisting of an initial dose using the ChAdOx platform and a secondary dose(s) using MVA encoding multiple hepatitis B antigens, including full-length surface, modified polymerase and core antigens. VTP-300 is the first antigen-specific immunotherapy that has been shown to induce sustained reductions in hepatitis B surface antigen.
Vaccitech is studying VTP-300 in combination with other agents, including siRNA and low-dose anti-PD-1 antibodies, to control the infection and counterbalance the immune suppression and T cell exhaustion in the liver caused by chronic HBV.
About hepatitis B
Globally it is estimated there are more than 300 million people, including up to 2.4 million in the U.S. and 14 million in Europe, living with chronic HBV infection. Prevalence is highest in East Asia and Africa. Fewer than 10% of patients with chronic HBV infection will achieve a functional cure by using existing therapies.
Approximately 820,000 people die each year from hepatitis B and related complications, such as liver cirrhosis and hepatocellular carcinoma (HCC). Hepatitis B diagnosis rates remain low and, as of 2019, only an estimated 10.5% of all those infected were aware of their infection.
As a result of low diagnosis rates and strict treatment eligibility guidelines, in 2019 only an estimated 6.6 million of the people with chronic HBV were on treatment.
Last year, Scancell Holdings, a developer of immunotherapies, in-licensed SNAPvax technology from Vaccitech. The aim is to initiate a phase 1 clinical study in cancer patients in 2024.