Tobevibart and Elebsiran Show High Virologic Response and ALT Normalization in Hepatitis Delta Patients After 12 and 24 Weeks

Vir Biotechnology, Inc. has announced new preliminary data from its Phase 2 SOLSTICE clinical trial, which evaluates tobevibart, an investigational monoclonal antibody, and elebsiran, an investigational small interfering ribonucleic acid, for chronic hepatitis delta treatment. The data indicate that both tobevibart alone and in combination with elebsiran achieved high rates of virologic response and ALT normalization, demonstrating potential as transformative treatments for this high unmet medical need.

The company plans to host an investor conference call on June 5 to discuss these data in detail. Additionally, these findings will be presented at the EASL Congress 2024 on June 8.

The preliminary data from the trial, involving six participants reported at the 2023 AASLD Liver Meeting, show sustained virologic response. Participants initially received 12 weeks of tobevibart or elebsiran monotherapy and then transitioned to combination therapy. All participants remain on treatment, with five having reached 48 weeks and one at 40 weeks of combination therapy. The results include 100% (6 of 6) achieving HDV RNA below the limit of detection or a significant decrease from baseline, 50% (3 of 6) achieving ALT normalization, and no serious adverse events recorded.

A separate de novo combination cohort of tobevibart and elebsiran showed rapid virologic suppression and ALT normalization. At week 12, all 27 participants achieved HDV RNA below the limit of detection or a significant decrease from baseline, with 44% achieving ALT normalization. By week 24, all 11 participants continued to show strong virologic suppression, with 64% reaching ALT normalization.

Tobevibart monotherapy also demonstrated high rates of virologic suppression and ALT normalization. At week 12, 73% of the 26 participants achieved significant HDV RNA reduction, with 54% achieving ALT normalization. These results were sustained in a subset at week 24.

The SOLSTICE trial is assessing the safety, tolerability, and efficacy of tobevibart and elebsiran in individuals with chronic hepatitis delta, including those with compensated cirrhosis. Tobevibart is engineered to inhibit the entry of hepatitis B and delta viruses into liver cells, neutralize virions, and reduce viral particles in the blood. Elebsiran targets hepatitis B virus RNA to limit viral production, featuring Enhanced Stabilization Chemistry Plus technology for increased stability and reduced off-target activity.

Tarik Asselah, M.D., Ph.D., emphasized the promise of these treatments in addressing chronic hepatitis delta, a severe form of viral hepatitis that can lead to cirrhosis and liver cancer. The preliminary SOLSTICE trial data show an impressive reduction in HDV RNA, surpassing previous therapies.

Vir Biotechnology is progressing with plans to report additional 24-week data for all SOLSTICE participants by the fourth quarter of 2024. The company is committed to working with regulatory authorities to expedite the availability of these treatments to patients in need.

The EASL oral presentation, scheduled for June 8, will provide further insights into the efficacy and safety of tobevibart and elebsiran in treating chronic hepatitis delta virus infection. The trial and its promising outcomes highlight Vir Biotechnology's ongoing efforts to develop effective treatments for viral-associated diseases.