Arbutus and Vaccitech Dose First Patient in Phase 2a Clinical Trial Combining Therapies for the Treatment of Chronic Hepatitis B Virus

Trial will evaluate AB-729, an RNAi therapy in combination with VTP-300, an immunotherapeutic, and NA therapy

Warminster, PA and Oxford, UK — Arbutus Biopharma Corporation (Nasdaq: ABUS), a clinical-stage biopharmaceutical company leveraging its extensive virology expertise to develop novel therapeutics that target specific viral diseases, and Vaccitech plc (Nasdaq: VACC), a clinical-stage biopharmaceutical company engaged in the discovery and development of novel immunotherapeutics and vaccines, today announced the first patient dosed in a Phase 2a clinical trial. This trial will evaluate Arbutus’ RNAi therapeutic candidate, AB-729, in combination with Vaccitech’s T-cell stimulating immunotherapeutic, VTP-300, and standard-of-care nucleos(t)ide reverse transcriptase inhibitor (NA) therapy for the treatment of patients with virologically-suppressed chronic HBV infection (cHBV).

Dr. Gaston Picchio, Chief Development Officer of Arbutus, stated, “To-date, we believe AB-729 is the only RNAi to show evidence of HBV-specific immune re-awakening. Through this collaboration, we have a unique opportunity to assess if the triple combination of AB-729, Vaccitech’s immunotherapeutic VTP-300 and NA therapy further enhances HBV-specific immune T-cell responses resulting in an incremental and sustainable reduction in HBsAg beyond what we have already seen with AB-729 and NA therapy alone. We are excited to explore these compounds in combination and we look forward to seeing results from this promising study.”

Dr. Tom Evans, Chief Scientific Officer for Vaccitech added, “Patients with HBV have high levels of HBsAg which can exhaust the immune system and prevent the clearance of HBV. By combining AB-729 with VTP-300, we are hoping to boost the immune system to manage the virus on its own by both reducing HBsAg levels and stimulating CD4+ and CD8+ T-cell responses in the liver.”

The randomized, multi-center, blinded, Phase 2a clinical trial will evaluate the safety, antiviral activity and immunogenicity of VTP-300 administered after AB-729 in virologically-suppressed cHBV patients. The trial is designed to enroll 40 cHBV patients. All patients will receive AB-729 (60mg every 8 weeks) plus NA therapy for 24 weeks.  At week 24, treatment with AB-729 will stop. Patients will continue only their NA therapy and will be randomized to receive either VTP-300 or placebo for an additional 24 weeks.  At week 48 all participants will be evaluated for eligibility to either discontinue or remain on NA therapy.