VIDEO: HBsAg loss with tobevibart, elebsiran combination ‘highly promising’ in chronic HBV

Key takeaways:

• Among patients with low baseline HBsAg, 39% achieved HBsAg loss with tobevibart/elebsiran, which rose to 46% with addition of PEG-IFN-a.
• Treatment-emergent adverse events were mild to moderate.

SAN DIEGO — Treatment with combination tobevibart and elebsiran led to hepatitis B surface antigen loss among 39% of patients with chronic HBV and low baseline HBsAg, which rose to 46% by adding pegylated interferon-alfa, data showed.

“Hepatitis B is a high unmet medical need, and approximately 250 million people around the world are chronically infected,” Mark D. Eisner, MD, chief medical officer at Vir Biotechnology, told Healio. “To date, there is no cure for hepatitis B.”

He continued, “What we’re aiming to achieve at Vir is what we call a functional cure — that means s-antigen loss that occurs by the end of our treatment period, in this case 44 to 48 weeks, and then can it be sustained 24 weeks or longer after the cessation of all treatment.”

In the phase 2 MARCH study, researchers enrolled patients with chronic HBV, who received Vir Biotechnology’s tobevibart 300 mg and elebsiran 200 mg alone every 4 weeks (doublet regimen; n = 51) or in combination with 180 mg PEG-IFN-a weekly (triplet regimen; n = 27).

According to late-breaking data presented at The Liver Meeting, HBsAg loss at the end of treatment was 39% in the doublet arm and 46% in the triplet arm, among patients with baseline HBsAg less than 1,000 IU/mL. Among those with varying baseline HBsAg levels, HBsAg loss was 16% and 22%, respectively.

Eisner noted the safety profile of tobevibart and elebsiran was “very acceptable,” with mild to moderate treatment-emergent adverse events.

“Taken together, we’re really excited about the data,” Eisner said. “We think these end-of-treatment responses in terms of s-antigen loss are highly promising and we’re looking forward to seeing the functional cure data next year.”

Reference:

• Vir Biotechnology announces positive end-of-treatment results for tobevibart and elebsiran combinations in chronic hepatitis B from the MARCH Study at AASLD The Liver Meeting. https://investors.vir.bio/news/news-details/2024/Vir-Biotechnology-Announces-Positive-End-of-Treatment-Results-for-Tobevibart-and-Elebsiran-Combinations-in-Chronic-Hepatitis-B-from-the-MARCH-Study-at-AASLD-The-Liver-Meeting/default.aspx. Published Nov. 15, 2024. Accessed Nov. 17, 2024.