Clinical testing begins for vaccine to treat hepatitis B
AVX70371 aims to spark immune response against infected cells
Astrivax Therapeutics has begun clinical testing of AVX70371, an experimental vaccine designed to treat hepatitis B.
“Starting clinical development with AVX70371 is the first step in the development of a new approach that could form the basis of a functional cure for chronic HBV [hepatitis B virus] infection,” Mathieu Peeters, MD, chief development officer of Astrivax, said in a company press release.
The company is sponsoring a Phase 1 clinical trial, dubbed RUBY (NCT06989788), testing up to three doses of AVX70371 in 16 healthy volunteers, with the main goal of evaluating the investigational treatment’s safety profile.
Astrivax said all participants have been given the first dose of AVX70371. The study is expected to run through the second half of 2026, with an interim analysis conducted before the end of this year.
Hepatitis B is a viral infection that causes liver inflammation (hepatitis). Some people, especially those infected when they’re young, will experience chronic, long-term infection that can set the stage for life-threatening complications like liver cancer and liver failure.
Vaccines can prevent infection
Vaccines that can prevent infection with the HBV virus are available, but nonetheless there are hundreds of millions of people worldwide with chronic HBV infection. Current hepatitis treatments can help keep the virus in check, but these need to be taken for the rest of a person’s life in order to be effective.
“Despite available preventive vaccines, chronic hepatitis B still affects over 250 million people worldwide, so there is an ongoing need for improved options for patients beyond life-long antiviral treatment,” said Hanne Callewaert, PhD, co-founder and CEO of Astrivax.
Distinct from preventive vaccines, which aim to prepare the immune system for a potential future infection and prevent the disease, therapeutic vaccines such as AVX70371 are designed to stimulate the immune system to target infected cells or viruses.
The body’s immune system can normally fight off viral infections, but people with chronic hepatitis B often experience HBV-specific immune exhaustion, when the immune system’s ability to battle the virus becomes impaired.
“AVX70371 has been designed to elicit a specific T-cell immune response against infected hepatocytes [liver cells] in which HBV is actively replicating,” Peeters said. “Knowing that patients with chronic hepatitis B suffer from immune exhaustion, this targeted immunotherapy approach is expected to intervene at the source of the chronic viral infection.”
AVX70371 was created using Astrivax’s Launched Immunotherapy (Launch-iT) technology platform, a tool to develop therapies that trigger the immune system to attack specific molecular targets.
A placebo-controlled Phase 1 trial (NCT06998004) tested two preventive vaccines for two viral diseases, yellow fever and rabies, developed using this tool. Data from the trial, which involved healthy adults, showed that both vaccines were generally well tolerated and effectively promoted immune responses against their respective disease-causing viruses, according to Astrivax.
“Following positive results from our first clinical study in 2024, which evaluated the safety and immunogenicity of our Launch-iT technology platform, starting the clinical development with our first therapeutic Launch-iT program is a significant milestone,” Callewaert said. A therapy’s immunogenicity refers to its ability to trigger an immune response.
Astrivax is currently working with the Launch-iT platform to create a therapeutic vaccine targeting persistent infection with the human papilloma virus (HPV), which can increase the risk of cancer in the cervix, the lower part of the uterus.
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