Vir Pressures Gilead with Promising Hepatitis D Phase 2 Cocktail

Vir Biotechnology is planning discussions with regulators regarding the future of its hepatitis D combination therapy. The company's early phase 2 trial results show promise, indicating that their drug combination could challenge Gilead Sciences' current efforts in this market.

Hepatitis D virus (HDV) requires the presence of the hepatitis B virus (HBV) to infect individuals. Those with both viruses face a significantly higher risk of severe liver damage and potentially fatal complications compared to those with only HBV. Currently, no treatments for hepatitis D are approved in the U.S. Vir aims to fill this gap with a drug combination designed to block viral entry, neutralize virus particles, and inhibit other viral activities.

On Wednesday, Vir presented initial data supporting their strategy. In their trial, six participants initially received either tobevibart or elebsiran as standalone treatments before starting the combination therapy. Out of five subjects who spent 48 weeks on the combination therapy, two met a combined endpoint, showing undetectable hepatitis D RNA levels and normal liver damage markers.

Furthermore, Vir shared findings from 27 patients who began treatment directly with the monthly drug combination. After 12 weeks, 12 of these patients met the combined endpoint. In a subset of 11 participants, the response rate was even higher after 24 weeks, with seven meeting the criteria.

The data indicated comparable response rates between those treated with tobevibart alone and those on the combination therapy. Although fewer participants on the monotherapy achieved a virologic response, the impact on liver damage markers was similar to that seen with the combination treatment.

These promising results suggest Vir's drug combination may outperform Gilead's bulevirtide, which has not demonstrated hepatitis D clearance and requires daily injections. A forthcoming clinical trial is expected to provide a clearer comparison between the two treatments. Carey Hwang, M.D., Ph.D., senior vice president of clinical research at Vir, discussed these plans during a call with investors.

"We are eager to engage with regulatory authorities in Q3 of this year to discuss the next steps for the development program. We anticipate that the next trial will use bulevirtide as a comparator, and we look forward to aligning the clinical development plan with health authorities. Additionally, we will explore all available acceleration pathways," Hwang stated.

Despite Vir's progress, Gilead may still be the first to reach the U.S. market with a hepatitis D treatment. Although the FDA rejected Gilead's initial approval request for bulevirtide in 2022 due to manufacturing and delivery issues, the company has resubmitted a revised filing. Bulevirtide, which Gilead acquired through its acquisition of MYR, is already approved for use in Europe.

In summary, Vir Biotechnology's early phase 2 trial results for its hepatitis D combination therapy show promise, potentially offering a more effective solution compared to Gilead's bulevirtide. As Vir moves forward with regulatory discussions and plans for further trials, the competitive landscape for hepatitis D treatments in the U.S. continues to evolve.