Vir Biotech's Hepatitis Drug Shows 88% Viral Suppression in New Data

SAN FRANCISCO, CA – January 12, 2026 – Vir Biotechnology has unveiled highly promising new clinical data for its combination therapy targeting chronic hepatitis delta (CHD), the most severe form of viral hepatitis. The results from the ongoing Phase 2 SOLSTICE trial show that 88% of patients treated with tobevibart and elebsiran achieved an undetectable viral load after 96 weeks, a significant finding that could pave the way for a new standard of care for a disease with notoriously limited treatment options.

The announcement, which also included key updates on the company's oncology pipeline and a fortified financial outlook, positions Vir for a pivotal year of clinical and corporate milestones. The San Francisco-based firm is advancing a dual-pronged strategy, tackling both challenging infectious diseases and solid tumor cancers with its proprietary technology platforms.

A New Horizon for Hepatitis Delta

The latest data from the Phase 2 SOLSTICE trial represents a potential breakthrough for patients with CHD, a condition recently classified as carcinogenic that often leads to rapid progression to liver failure and death. The trial evaluated a combination of tobevibart, an investigational neutralizing monoclonal antibody, and elebsiran, an investigational small interfering RNA (siRNA).

At the 96-week mark, 88% (21 of 24) of participants who received the monthly combination therapy had undetectable levels of hepatitis delta virus (HDV) RNA. This result shows a marked improvement over time, increasing from 77% at Week 72. The efficacy of the combination was further underscored when compared to treatment with tobevibart alone, where only 46% of participants achieved undetectable viral levels at Week 96. The combination therapy was reported to be well-tolerated, with no severe treatment-related adverse events.

These results are particularly significant when viewed against the current treatment landscape. In Europe, the approved treatment is bulevirtide, an entry inhibitor that has demonstrated a combined response (virological response and liver enzyme normalization) in approximately 55% of patients at 96 weeks in its own pivotal trials. While direct head-to-head comparisons are complex, Vir's reported 88% viral suppression rate suggests a potentially superior efficacy profile. The company is already conducting a head-to-head trial (ECLIPSE 3) against bulevirtide to provide supportive data for reimbursement and market access.

"The latest data from our SOLSTICE Phase 2 trial evaluating tobevibart and elebsiran combination therapy in CHD are very promising, showing that monthly treatment with this combination therapy has the potential to achieve an undetectable viral load in a large number of patients, which could redefine the standard of care in CHD,” said Marianne De Backer, Ph.D., Chief Executive Officer, Vir Biotechnology, in a statement.

Building on these results, Vir is advancing its registrational ECLIPSE program, with topline data from the pivotal ECLIPSE 1 trial expected in the fourth quarter of 2026. Success in this program could lead to the first approved therapy for CHD in the United States, where no treatments are currently available.

Beyond Viruses: A 'Smart Bomb' Approach to Cancer

While its hepatitis program moves toward the finish line, Vir is simultaneously making strides with a sophisticated oncology pipeline built on its PRO-XTEN® dual-masked T-cell engager (TCE) platform. This technology is designed to solve a critical problem in cancer therapy: toxicity.

TCEs are powerful drugs that act like a bridge, connecting a patient's own T-cells to cancer cells to trigger their destruction. However, their potency can also lead to severe side effects when they attack healthy tissues that express the same target as the cancer. Vir’s PRO-XTEN® technology adds a "mask" to the TCE, keeping it inactive in the bloodstream. This mask is designed to be cleaved off only by proteases that are highly concentrated within the tumor microenvironment, effectively creating a "smart bomb" that activates primarily at the site of the cancer. This approach aims to dramatically improve the safety and tolerability of these powerful agents.

The company's lead oncology candidate, VIR-5500, targets PSMA, a protein highly expressed on prostate cancer cells. Vir announced it will present updated Phase 1 safety and efficacy data for VIR-5500 in metastatic castration-resistant prostate cancer (mCRPC) at the American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium in February. This presentation is highly anticipated and will provide a deeper look at the drug's dose-response relationship and durability in late-line patients.

Vir's oncology ambitions extend further, with two other masked TCEs in Phase 1 trials: VIR-5818 targeting HER2-expressing solid tumors and VIR-5525 targeting EGFR-expressing tumors. Both HER2 and EGFR are validated but challenging cancer targets where managing toxicity is paramount. Dose escalation response data for the HER2-targeted program are expected in the second half of 2026, further testing the breadth of the PRO-XTEN® platform.

Strategic Deals and Financial Fortitude

Underpinning its ambitious clinical development is a series of shrewd strategic moves that have secured Vir's financial stability. Last month, the company entered into an exclusive licensing agreement with Norgine Pharma for the commercial rights to its CHD combination therapy in Europe, Australia, and New Zealand.

The deal provides Vir with a €55 million upfront payment and the potential for up to €495 million in future milestones, plus tiered royalties ranging from the mid-teens to high-twenties. Norgine, a specialty pharmaceutical company with deep roots in hepatology, will manage commercialization in these key international markets, allowing Vir to focus its resources on the sizable U.S. market.

This non-dilutive funding, combined with what the company calls "continued financial discipline," has significantly extended its financial runway. Vir reported an unaudited cash position of approximately $781 million as of December 31, 2025, and now expects its funds to last into the fourth quarter of 2027. This financial security is crucial, providing the necessary capital to advance its late-stage CHD program and early-stage oncology pipeline through multiple critical data readouts without immediate pressure to raise additional funds.

With pivotal data on the horizon for its potentially best-in-class hepatitis delta therapy and a stream of updates expected from its innovative cancer platform, Vir Biotechnology has positioned 2026 to be a year of significant transformation, moving from a clinical-stage developer to a potential commercial powerhouse in two of medicine's most challenging fields.