Vir Biotechnology Provides Updates on Chronic Hepatitis Delta and Oncology Programs and Upcoming 2026 Clinical Milestones
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Positive, updated Phase 2 SOLSTICE data showed combination of tobevibart and elebsiran is well tolerated and achieved undetectable HDV RNA in 88% of chronic hepatitis delta participants evaluable at 96 Weeks of treatment
– New Phase 1 data from PSMA-targeted PRO-XTEN®dual-masked T-cell engager VIR-5500 in prostate cancer to be presented at the 2026
– Year-end 2025 cash and investments balance of approximately
The Company also announced that safety and efficacy data from the Phase 1 trial of VIR-5500, its PSMA-targeted PRO-XTEN® dual-masked T-cell engager (TCE) being evaluated in prostate cancer, will be shared in an oral presentation at the 2026
“We are poised for a year of significant clinical progress where we will report initial topline data from our Phase 3 program in CHD, present substantive Phase 1 safety and efficacy data from our PSMA-targeted VIR-5500 TCE program and continue to advance our broader portfolio of PRO-XTEN® masked TCEs through dose escalation,” said
Recent Updates and 2026 Clinical Milestones
Tobevibart and elebsiran combination therapy for CHD
Data from the Phase 2 SOLSTICE trial to be presented at the 44ᵗʰ Annual
The registrational ECLIPSE program in CHD is ongoing, with ECLIPSE 1 and ECLIPSE 3 fully enrolled. Topline data from the ECLIPSE 1 trial is expected in the fourth quarter of 2026. Topline data from the ECLIPSE 2 and ECLIPSE 3 trials are expected in the first quarter of 2027.
Last month,
PRO-XTEN® dual-masked TCE immunotherapy portfolio
PSMA-targeted PRO-XTEN® dual-masked TCE VIR-5500 is currently being evaluated as monotherapy and in combination with androgen receptor pathway inhibitors (ARPIs) for the first-line treatment of metastatic castration-resistant prostate cancer (mCRPC).
Additionally, the Company is currently progressing a number of PRO-XTEN® masked TCEs in preclinical studies directed at clinically validated targets with potential applications across a variety of solid tumors, including lung, colorectal and bladder. All candidates have been discovered and optimized by leveraging Vir Biotechnology’s antibody and TCE discovery and engineering platform, which includes dAIsY™ (data AIstructure and antibodY), a proprietary artificial intelligence engine, and the universal PRO-XTEN® masking technology.
2025 ending cash position (unaudited) and runway projection
Cash, cash equivalents and investments were approximately
About the ECLIPSE Registrational Program
ECLIPSE is a registrational program to evaluate the safety and efficacy of tobevibart in combination with elebsiran in patients with chronic hepatitis delta (CHD). ECLIPSE includes three randomized, controlled trials designed to evaluate the combination therapy in comparison to deferred treatment or bulevirtide. ECLIPSE 1 (NCT06903338) is a Phase 3 trial evaluating the safety and efficacy of tobevibart in combination with elebsiran compared to deferred treatment in the
About Tobevibart and Elebsiran
Tobevibart is an investigational broadly neutralizing monoclonal antibody (mAb) targeting the hepatitis B surface antigen (HBsAg). It is designed to inhibit the entry of hepatitis B and hepatitis delta viruses into hepatocytes and to reduce the level of circulating viral and subviral particles in the blood. Tobevibart was identified using Vir Biotechnology’s proprietary mAb discovery platform. The Fc domain has been engineered to increase immune engagement and clearance of HBsAg immune complexes and incorporates Xencor’s Xtend™ technology to extend half-life. Tobevibart is administered subcutaneously, and it is currently in clinical development for the treatment of patients with chronic hepatitis delta.
Elebsiran is an investigational hepatitis B virus-targeting small interfering ribonucleic acid (siRNA) licensed from Alnylam Pharmaceuticals, Inc. It is designed to degrade hepatitis B virus RNA transcripts and limit the production of HBsAg. Current data indicate that it has the potential to have direct antiviral activity against hepatitis B virus and hepatitis delta virus. Elebsiran is administered subcutaneously, and it is currently in clinical development for the treatment of patients with chronic hepatitis delta.
About
CHD is the most severe form of chronic viral hepatitis4 and was recently classified as carcinogenic by the
About VIR-5500, VIR-5818, VIR-5525
VIR-5500, VIR-5818 and VIR-5525 are investigational, clinical candidates currently being evaluated for the treatment of solid tumors. These assets leverage the universal PRO-XTEN® masking technology and target PSMA, HER2 and EGFR, respectively.
TCEs are powerful anti-tumor agents that can direct the immune system, specifically T-cells, to destroy cancer cells. The universal PRO-XTEN® masking technology is designed to keep the TCEs inactive (or masked) until they reach the tumor microenvironment, where tumor-specific proteases cleave off the mask and activate the TCEs, leading to killing of cancer cells. By driving the activity exclusively to the tumor microenvironment, we aim to circumvent the traditionally high toxicity associated with TCEs and increase their efficacy and tolerability. Additionally, the mask is designed to help drug candidates stay in the bloodstream longer in their inactive form, allowing them to better reach the site of action and potentially allowing less frequent dosing regimens for patients and clinicians.
About
Footnotes and references:
1 These preliminary selected financial results are unaudited and subject to adjustment. The Company expects to report its final and complete fourth quarter and full-year 2025 financial results in late
2 Asselah T, Chattergoon MA, Jucov A, et al. A Phase 2 Trial of Tobevibart plus Elebsiran in Hepatitis D. N Engl J Med. 2025 Nov 9.Online ahead of print. doi:10.1056/NEJMoa2508827.
3 People’s
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5 Karagas, Margaret R et al., Carcinogenicity of hepatitis D virus, human cytomegalovirus, and Merkel cell polyomavirus, The Lancet Oncology, Volume 26, Issue 8, 994 – 995.
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Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “should,” “could,” “may,” “might,” “will,” “plan,” “potential,” “aim,” “expect,” “anticipate,” “promising” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements regarding: Vir Biotechnology’s belief that 2026 will be a year of significant clinical progress for its CHD and oncology TCE programs; the therapeutic and commercial potential of Vir Biotechnology’s CHD program and Vir Biotechnology’s belief that the monthly treatment with the combination of tobevibart and elebsiran has the potential to achieve an undetectable viral load in a large number of patients, which could redefine the standard of care in CHD; Vir Biotechnology’s clinical development plans and expectations for the ECLIPSE Phase 3 registrational program, including protocols for and enrollment into ongoing and planned clinical trials, target endpoints and data analyses or readouts (including the expectation of topline data for ECLIPSE 1 in the fourth quarter of 2026 for ECLIPSE 2 and ECLIPSE 3 in the first quarter of 2027); the therapeutic and potential of Vir Biotechnology’s oncology solid tumor portfolio, preclinical pipeline and PRO-XTEN® masking technology; Vir Biotechnology’s clinical development plans and expectations for the VIR-5500 and VIR-5818 Phase 1 programs, including protocols for and enrollment into ongoing and planned clinical trials, target endpoints and data analyses or readouts (including plans to share updated Phase 1 data for VIR-5500 at the 2026 ASCO Genitourinary Cancers Symposium in
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