Vir Biotechnology, Inc, an advanced-stage biopharmaceutical firm dedicated to utilizing the immune system for medical breakthroughs in severe infectious diseases and cancer, has announced that the US Food and Drug Administration has granted breakthrough therapy designation to tobevibart and elebsiran, alongside receiving the European Medicines Agency (EMA) Priority Medicines (PRIME) designation, for addressing chronic hepatitis delta (CHD).
These acknowledgments are based on promising safety and efficacy outcomes observed in the phase 2 SOLSTICE study, details of which were recently shared at the AASLD Liver Meeting in San Diego, USA. Vir Biotechnology is planning to launch its phase 3 ECLIPSE program in the first half of 2025, aiming to assess the effectiveness of tobevibart and elebsiran in tackling chronic hepatitis delta.
Chronic hepatitis delta, driven by the hepatitis delta virus, represents the most severe chronic viral hepatitis, posing increased risks for liver cancer, and hastening the development of cirrhosis and liver failure. Despite the severity, no treatments have been licensed within the US, and only limited options are available across the European Union and globally.
“Chronic hepatitis delta has significant detrimental impacts on liver functionality and overall health, yet individuals living with this illness still lack profoundly effective treatment solutions,” stated Mark Eisner, executive vice president and chief medical officer of Vir Biotechnology. “Evidence from the phase 2 SOLSTICE trial indicates that tobevibart and elebsiran have the capability to significantly reduce the hepatitis delta virus, achieving undetectable levels. Recognition as breakthrough therapy and receiving the PRIME designation underscores the potential this combination holds in revolutionizing treatment for those with CHD. We are eager to expedite the progression of the phase 3 ECLIPSE initiative.”
The US FDA’s breakthrough therapy designation is designed to accelerate the development and review process for investigational drugs showing promising initial clinical data and potential enhancements over existing therapies for serious conditions. Meanwhile, EMA’s PRIME designation is aimed at investigational drugs targeting unmet medical needs or offering a substantial therapeutic advantage over current treatments, promoting early agency interaction to ensure the collection of comprehensive data, high-quality marketing submissions, and faster evaluations to hasten patient access. These designations follow a prior FDA Fast Track designation and a positive opinion on an orphan drug designation from EMA’s Committee for Orphan Medicinal Products earlier this year.
SOLSTICE is a phase 2 trial assessing the safety, tolerability, and effectiveness of tobevibart, alone or combined with elebsiran, in individuals with chronic hepatitis delta. It is a multi-center, open-label, randomized study. Primary objectives include the percentage of participants with non-detectable hepatitis delta virus (HDV) RNA (designated as HDV RNA equal or exceeding a reduction of 2 log10 from baseline or undetectable) up to week 24, alanine aminotransferase (ALT) normalization (ALT under the upper normal limit) up to week 24, and the tracking of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs) for up to 118 weeks. Secondary goals encompass the proportion of participants with non-detectable HDV RNA at specified timepoints and up to 192 weeks.
Tobevibart, an investigational broad-spectrum monoclonal antibody, targets the hepatitis B surface antigen, designed to thwart the entry of hepatitis B and delta viruses into liver cells while diminishing the presence of circulating viral and subviral particles in the bloodstream. Utilizing Vir’s proprietary antibody discovery system, Tobevibart has been developed with Xencor’s Xtend and other Fc technologies for an extended half-life, currently under clinical trials for patients with either chronic hepatitis B or delta. Administered subcutaneously, its development continues.
Elebsiran, a trial-phase small interfering RNA targeting hepatitis B virus RNA, works to degrade RNA transcripts and curb hepatitis B surface antigen production. Preliminary data highlight its potential antiviral efficacy against both B and delta viruses. Currently evaluated in clinical settings, elebsiran is also administered subcutaneously to patients with either chronic hepatitis B or delta.
Overall, Vir Biotech’s innovations are poised to significantly advance therapeutic options available for chronic hepatitis delta, aiming to satisfy significant unmet medical needs worldwide.