Vir Biotechnology (VIR) Q3 2026 Earnings Call: ECLIPSE Data and Gilead Deal

Vir Biotechnology (NASDAQ: VIR) ended Q3 2026 with $901 million in cash, cash equivalents and investments, while advancing three Phase III hepatitis delta trials and expanding its oncology partnerships. The company expects key ECLIPSE data readouts through Q1 2027 and projects its cash runway will extend into the second half of 2028.

Key Takeaways

• Vir ended Q3 2026 with $901 million in cash, cash equivalents and investments. This excludes $90 million received from Gilead in October.
• Management expects Phase III ECLIPSE-1 topline data in Q4 2026, followed by ECLIPSE-2 and ECLIPSE-3 results in Q1 2027.
• Q3 R&D expense fell to $80 million from $151 million a year earlier, mainly because Q3 2025 included a one-time $75 million milestone payment related to VIR-5525.
• VIR-5500 achieved proof of concept based on clinical, safety, pharmacology and biomarker data. The FDA also granted Fast Track designation in late-line metastatic castration-resistant prostate cancer.
• The Gilead collaboration delivered $65 million upfront and a $25 million equity investment at a 30% premium. Vir is eligible for up to $45 million in near-term preclinical milestones and up to $1.74 billion in additional milestones.
• Based on its current operating plan, management projects that available cash will fund operations into the second half of 2028.

Core Financial Data

Business and Operating Performance

Hepatitis delta Phase III program

Vir’s Phase III ECLIPSE program is evaluating the monthly subcutaneous combination of elebsiran and tobevibart across treatment-naive patients, patients switching from bulevirtide and a head-to-head comparison with bulevirtide.

ECLIPSE-1 enrolled approximately 120 treatment-naive participants randomized 2:1 between the combination regimen and deferred treatment. Its primary endpoint is HDV RNA target not detected, or TND, combined with ALT normalization at week 48.

ECLIPSE-2 enrolled approximately 150 patients with an inadequate response to bulevirtide. Participants were randomized 2:1, and the primary endpoint is HDV RNA TND at week 24.

ECLIPSE-3 enrolled approximately 100 treatment-naive patients randomized 2:1 between Vir’s combination and bulevirtide. Its primary endpoint is HDV RNA TND at week 48.

Management said Phase II SOLSTICE data showed TND in approximately 66% of patients after 48 weeks. The company believes the regimen’s antiviral activity and once-monthly administration could differentiate it from daily bulevirtide treatment.

VIR-5500 prostate cancer program

VIR-5500, a dual-masked PSMA-targeted T-cell engager co-developed with Astellas, achieved proof of concept based on the totality of efficacy, safety, pharmacology and biomarker data generated to date.

The FDA granted VIR-5500 Fast Track designation for late-line metastatic castration-resistant prostate cancer. A Phase I trial is evaluating monotherapy and combination therapy across six dose-expansion cohorts, including taxane-naive, radioligand therapy-naive and radioligand therapy-exposed mCRPC, as well as metastatic hormone-sensitive prostate cancer.

Vir and Astellas aim to initiate multiple Phase III trials in early- and late-line settings during 2027. The companies are also working on manufacturing readiness.

Other oncology programs

VIR-5818, Vir’s HER2-targeted T-cell engager, remains in Phase I development as monotherapy and in combination with pembrolizumab. Following FDA feedback, Vir plans to add monotherapy backfill cohorts in a more homogeneous patient population to refine dose and schedule selection. The dataset is therefore not yet complete, and the company no longer plans to provide the previously anticipated 2026 update.

VIR-5525, an EGFR-targeted T-cell engager, continues dose escalation as monotherapy and in combination with pembrolizumab across lung, colorectal, head and neck squamous cell, and cutaneous squamous cell cancers.

Gilead collaboration

Under the multi-program research collaboration, Vir will discover, design and optimize three PRO-XTEN masked T-cell engager development candidates for solid tumor targets. Gilead will hold exclusive rights to advance the candidates and will manage subsequent development, manufacturing and commercialization.

In addition to the $90 million initial consideration, Vir is eligible for up to $45 million in near-term preclinical milestones and up to $1.74 billion in additional development, regulatory and commercial milestones. The agreement also includes tiered high-single-digit to low-double-digit royalties.

Vir said the previous 20% pass-through economics to Sanofi had expired before the agreement, meaning collaboration milestone payments will not be shared with Sanofi.

Management Guidance

• ECLIPSE-1 topline results are expected in Q4 2026.
• ECLIPSE-2 and ECLIPSE-3 topline results are expected in Q1 2027.
• Vir plans to provide a broader immuno-oncology strategy update at a virtual research investor event in Q1 2027.
• Vir and Astellas aim to initiate multiple VIR-5500 Phase III studies during 2027, subject to ongoing registrational planning.
• Management projects that cash will fund operations into the second half of 2028 under the current operating plan.

Risks and Watch Items

The ECLIPSE program’s registrational outcomes remain dependent on pending Phase III data. ECLIPSE-1 must assess a composite endpoint of TND and ALT normalization, while ECLIPSE-2 and ECLIPSE-3 use TND-only primary endpoints at different time points.

For VIR-5818, FDA feedback led Vir to refine the monotherapy study and add backfill cohorts. Management said the dataset remains incomplete and did not provide a new timing commitment for a clinical update.

Vir did not disclose updated VIR-5500 response durability data or detailed proof-of-concept criteria. Additional clinical information may be presented before pivotal trials begin.

Analyst Q&A Highlights

• ECLIPSE-1 disclosure: Management expects to report the composite primary endpoint, relevant secondary endpoints, cirrhosis subgroup information, and safety and tolerability data.
• ECLIPSE-3 competitive threshold: Management cited bulevirtide TND rates of roughly 12% to 20% after 48 weeks and compared them with approximately 66% in the Phase II SOLSTICE study, but did not specify the minimum difference required for clinical or commercial success.
• HDV commercialization preparation: Vir has conducted market research with healthcare professionals and payers, assessed diagnostic trends, and evaluated distribution channels for both at-home and healthcare-provider administration.
• Bulevirtide switching opportunity: Management pointed to rapid ECLIPSE-2 enrollment as an indicator of demand among patients inadequately controlled on bulevirtide. The trial is also generating switching data relevant to concerns about flares.
• VIR-5500 pivotal development: Vir plans to target both early- and late-line prostate cancer settings but will provide specific Phase III designs with Astellas at a later date.

Full Earnings Call Transcript

Complete Earnings Call Transcript

Management Remarks

Operator

Hello, and welcome to Vir Biotechnology's Third Quarter 2026 Financial Results and Corporate Update Conference Call. As a reminder, this call is being recorded.

[Operator Instructions] I will now turn the call over to Kiki Patel, Head of Investor Relations. You may begin, Kiki.

Kiki Patel

Thank you, operator, and welcome, everyone. Earlier today, we issued a press release reporting our third quarter 2026 financial results and corporate update.

Before we begin, I'd like to remind everyone that some of the statements we are making today are forward-looking statements under applicable securities laws. Forward-looking statements include, but are not limited to, statements regarding the therapeutic and commercial potential of our clinical and preclinical programs, our development plans and time lines, our collaborations with other companies, our cash runway and capital allocation priorities and as otherwise described in the legal disclaimers accompanying our public presentations. These forward-looking statements involve substantial risks and uncertainties, which are described in our reports filed with the Securities and Exchange Commission, including our Forms 10-K, 10-Q, and 8-K, and could cause future results, performance or achievements to differ significantly from those expressed or implied by such forward-looking statements.

Joining me on today's call from Vir Biotechnology are Dr. Marianne De Backer, our President and Chief Executive Officer; and Aziz Sawaf, our Chief Financial Officer.

The agenda for our call today is as follows: First, Marianne will provide a strategic update on where Vir Bio stands today, including an overview of our Phase III registrational program in hepatitis delta. Next, she will review the latest updates across the PRO-XTEN dual mass T-cell engager program and present the highlights of our recently announced preclinical collaboration with Gilead. Next, Aziz will review the financial terms of our recent collaboration with Gilead and provide a summary of our third quarter 2026 financial results. And finally, Marianne will close the call, and we'll open the line for Q&A.

With that, I'll now turn the call over to Marianne.

Marianne De Backer

Thank you, Kiki. Good afternoon, everyone, and thank you for joining us for Vir Biotechnology's Third Quarter 2026 Financial Results Conference Call. We are entering a pivotal period for Vir Bio with the potential to transform hepatitis delta treatment while building a differentiated oncology franchise.

Today, I will highlight significant progress across both those areas and why we believe Vir Bio is well positioned for meaningful value creation ahead. First, we've expanded our leadership team with the addition of Aziz Sawaf as Chief Financial Officer; and Dr. David Liu as Chief Medical Officer. Both bring more than 20 years of experience in their respective fields, further bolstering our capabilities as we enter an important period for Vir Bio. With our leadership team strengthened, we are well positioned to execute against the significant opportunities and catalysts ahead.

Second, our hepatitis delta program continues to advance through Phase III development. We expect to report top line data from ECLIPSE-1 this quarter, followed by top line data from ECLIPSE-2 and ECLIPSE-3 in the first quarter of 2027. We will also present expanded 96-week Phase II SOLSTICE results in an oral presentation at AASLD this weekend.

Third, we have made meaningful progress across our oncology portfolio. Astellas recently announced that VIR-5500 achieved proof of concept, reinforcing the scientific rationale for advancing the program into late-stage development. In addition, we are pleased to share that the FDA granted Fast Track designation to VIR-5500 for the treatment of late-line metastatic castration-resistant prostate cancer.

And finally, our recent research collaboration with Gilead underscores the potential of our PRO-XTEN platform and highlights the strength of our integrated AI-enabled capabilities in T-cell engager discovery and optimization. This collaboration represents the second major external validation of the PRO-XTEN masking technology in the last 8 months, following our partnership with Astellas on VIR-5500 in February. Overall, these achievements position us well to execute on our strategic priorities and deliver against the important catalysts ahead.

Now starting with our hepatitis delta program. Chronic hepatitis delta remains one of the most severe and underserved forms of viral liver disease. October was Liver Cancer Awareness Month and the World Hepatitis Alliance has focused on amplifying the message that hepatitis elimination is liver cancer prevention. Hepatitis delta is associated with a two- to six-fold higher risk of liver cancer compared to hepatitis B alone and was classified as carcinogenic by the World Health Organization's International Agency for Research on Cancer last year.

While recent advances have expanded treatment options for patients, there remains a critical need for therapies capable of delivering deeper antiviral activity and more complete disease control. Current approaches have generally focused on decreasing the viral load, but many patients continue to have detectable HDV RNA despite treatment. Hepatologists and treating physicians believe that achieving complete viral elimination to where the virus is undetectable, defined by HDV RNA target not detected or TND, represents an important next frontier in hepatitis delta care, representing deeper disease control and potential clinical benefit for patients.

Building on the encouraging TND results observed in our Phase II SOLSTICE trial, the ECLIPSE program is designed to determine whether this approach can consistently deliver profound viral suppression across key populations. ECLIPSE-1 is designed to provide the first Phase III assessment of the proportion of patients who can achieve undetectable HDV RNA after 48 weeks of treatment with our combination regimen of elebsiran and tobevibart. The trial has enrolled approximately 120 participants randomized 2:1 to monthly subcutaneous dosing of our combination regimen versus deferred treatment in treatment-naive patients with chronic hepatitis delta. The primary endpoint is a composite of HDV RNA TND together with ALT normalization at week 48.

ECLIPSE-2 has enrolled approximately 150 patients who are being randomized 2:1, evaluating the switch to our combination therapy in patients who have an inadequate response to bulevirtide. The primary endpoint for the trial is undetectable virus as defined by HDV RNA TND at week 24. The pace of enrollment we observed in Europe for this trial reflects an important unmet need in patients previously treated with bulevirtide.

ECLIPSE-3 is our pivotal head-to-head trial against bulevirtide in treatment-naive patients. We have enrolled approximately 100 patients randomized 2:1 to our combination therapy versus bulevirtide. The primary endpoint for the trial is undetectable virus as defined by HDV RNA TND at week 48. Together, ECLIPSE-1, ECLIPSE-2 and ECLIPSE-3 are expected to provide a comprehensive data package, generating data in treatment-naive patients, patients switching from bulevirtide and patients enrolled in a head-to-head comparison against bulevirtide.

As bulevirtide utilization grows, physicians will need evidence-based guidance on how best to manage patients who do not achieve adequate file suppression or who require an alternative treatment approach. To our knowledge, no other late-stage HDV development program is expected to include comparable bulevirtide switch or head-to-head data in its regulatory submission package, potentially providing a uniquely comprehensive evidence base for physicians, payers and regulators. Collectively, these studies are designed to position our program at the very forefront of the evolving hepatitis delta treatment landscape and ultimately improve outcomes for patients living with this devastating disease.

Turning now to oncology. VIR-5500 is our PRO-XTEN dual-masked PSMA-targeted T-cell engager, which we are advancing in a global co-development and co-commercialization collaboration with Astellas for prostate cancer. Astellas already shared on its earnings call yesterday that VIR-5500 has achieved proof of concept, reinforcing the scientific rationale for advancing the program into registrational trials. This assessment reflects the totality of the clinical, safety, pharmacology and biomarker data generated to-date and supports continued investment in the registrational planning and execution.

We also recently announced that the FDA granted Fast Track designation to VIR-5500 for the treatment of late-line metastatic castration-resistant prostate cancer, or mCRPC, underscoring VIR-5500's potential to address a significant unmet need in patients who have limited treatment options. Both of these milestones highlight the strong progress we have made with our partner, Astellas, as we advance the program towards pivotal trials.

VIR-5500 is currently being evaluated in a Phase I trial as both a monotherapy and combination therapy across 6 dose expansion cohorts. Indications include Taxane-naive mCRPC, radioligand therapy-naive mCRPC, radioligand therapy exposed mCRPC, and metastatic hormone-sensitive prostate cancer. These expansion studies are designed to inform the next phase of development with the goal of initiating multiple Phase III studies spanning both early-line and late-line settings in 2027.

In parallel, we are focused on advancing manufacturing readiness in collaboration with Astellas. Importantly, our plans to pursue first-line mCRPC reflect our belief that VIR-5500 has the potential to become a foundational therapy across the prostate cancer treatment continuum.

Moving now to VIR-5818, our HER2-targeted T-cell engager. This program is currently being evaluated in a Phase I trial with dose escalation and signal finding components, both as monotherapy and in combination with pembrolizumab. The trial has enrolled patients with a variety of HER2-expressing cancers.

During our last update on the program, we shared encouraging antitumor activity and a generally well-tolerated safety profile. While we had previously anticipated providing a data update on the program this year, recent FDA feedback on the monotherapy arm has led us to refine the study. We intend to add backfill cohorts in a more homogeneous patient population to help determine the optimal dose and schedule, which is aligned with FDA's Project Optimus, an initiative to reform the dose optimization and dose selection paradigm in oncology drug development.

As a result, the study remains ongoing and the data set is not yet complete. In parallel, dose escalation and optimization of VIR-5818 in combination with pembrolizumab is ongoing. We anticipate presenting a meaningful update on VIR-5818 at a future scientific conference. Finally, VIR-5525, our EGFR-targeted T-cell engager continues to progress through dose escalation in both monotherapy and combination therapy with pembrolizumab across lung cancer, colorectal cancer, head and neck squamous cell carcinoma, and cutaneous squamous cell carcinoma.

Looking ahead, our preclinical immuno-oncology pipeline is fueling a growing oncology portfolio. We are in a fortunate position where the breadth of opportunities generated by our scientific platform exceeds what we can advance independently, allowing us to be strategic about which programs we progress ourselves. In the first quarter of 2027, we plan to provide a more comprehensive view of the next chapter of our cancer immunotherapy strategy at a virtual research investor event.

We will provide investors with a road map for how we plan to build and scale a world-class immuno-oncology franchise. The breadth of our pipeline does not mean we will advance every opportunity ourselves. We intend to be disciplined in how we allocate capital, concentrating investment where our capabilities are most differentiated and partnering strategically where collaboration can accelerate development, expand reach and maximize the impact of our platform for patients.

Our research collaboration with Gilead is an example of this strategy in action, providing further external validation of the PRO-XTEN platform and the potential to deliver T-cell engagers with an improved safety profile. This preclinical multi-program collaboration leverages Vir Bio's integrated expertise in T-cell engager discovery and protein engineering. Our proprietary dAIsY platform for rapid multiparameter optimization of high-quality T-cell engagers and the PRO-XTEN masking technology to develop next-generation T-cell engagers across multiple solid tumor targets.

Under the agreement with Gilead, Vir Bio will be responsible for the discovery, design and optimization of 3 PRO-XTEN Mas T-cell engager development candidates with the potential to address multiple solid tumor indications with significant unmet medical need. Gilead will have the exclusive rights to advance candidates generated through the collaboration and will be responsible for subsequent development, manufacturing, and commercialization.

With that, I'll now hand the call over to Aziz, who will walk through the financial terms of our Gilead collaboration and our third quarter financial results.

Aziz Sawaf

Thanks, Marianne. Before I begin, I'd like to say how pleased I am to have joined Vir Bio at this exciting time for the company. I look forward to working with the team to build on the company's progress and help translate the strength of the portfolio into long-term value for shareholders and patients. The Gilead collaboration is a strong example of that opportunity.

As Marianne discussed, the agreement provides further validation of our oncology platform while increasing our financial flexibility. It also demonstrates how selective partnerships can preserve meaningful long-term value and support disciplined capital allocation. Under the agreement, we received $90 million, consisting of $65 million upfront and a $25 million equity investment at a 30% premium. We are also eligible to receive up to $45 million in near-term preclinical milestones.

Beyond that, we have the potential to receive up to $1.74 billion in additional development, regulatory and commercial milestones, along with tiered high single to low double-digit royalties. Importantly, the 20% pass-through economics to Sanofi has expired and were no longer in effect at the time of the agreement. As a result, none of the milestone payments from this collaboration will be shared with Sanofi.

Turning to our Q3 financial results, where I'll focus on a few key metrics. R&D expense was $80 million compared with $151 million for the same period in 2025. The reduction was primarily driven by a onetime $75 million milestone payment recognized in the third quarter of 2025, following the first patient dosed with VIR-5525. SG&A expense was $24 million compared with $22 million for the same period in 2025. The increase was primarily due to higher advisory and legal fees. We ended the quarter with $901 million in cash, cash equivalents and investments.

Importantly, this balance does not include the $90 million upfront from the Gilead collaboration, which was received in October. Based on our current operating plan, we project that our cash will fund operations into the second half of 2028.

As we look ahead, we will remain thoughtful and disciplined in how we deploy capital. Our focus will be on supporting the company's highest priority programs, preserving financial flexibility around important inflection points and ensuring that our investments remain aligned with the potential to create long-term value for shareholders and patients.

With that, I'll turn the call back to Marianne, to conclude. Marianne?

Marianne De Backer

Thank you, Aziz. In summary, I'm incredibly proud of the strong execution we have delivered in the third quarter of this year. In hepatitis delta, the totality of evidence generated from our SOLSTICE program continues to reinforce our confidence in the potential of elebsiran and tobevibart to offer a highly differentiated treatment profile. Combined with once-monthly subcutaneous administration and the potential for both at-home or health care provider administration, we believe our regimen could become a best-in-class treatment option capable of redefining expectations for patients. We look forward to sharing the top line results of our Phase III ECLIPSE-1 trial later this quarter and ECLIPSE-2 and ECLIPSE-3 trials in the first quarter of next year.

In oncology, VIR-5500 continues to advance rapidly. Following the Fast Track designation granted last month and with expansion cohorts actively enrolling, we and Astellas look forward to sharing more on our registrational development plans next year. Furthermore, the collaboration we announced with Gilead further validates our integrated drug discovery capabilities and demonstrates our ability to create value through strategic partnerships that both extend the reach of our technology and help support investment in our wholly-owned oncology portfolio. Taken together, these developments reinforce our confidence in the breadth of the platform and help further define the path forward for the program.

I'm excited about what we have built and the opportunity ahead. We have the potential to redefine the treatment paradigm in hepatitis delta, advance a new treatment approach in prostate cancer and bring other important new therapies to patients. And finally, we are entering this next phase from a position of financial strength, well capitalized and poised for what we believe will be a transformative period in our company's history.

With that, I'll turn the call over to Kiki, to begin the Q&A session.

Kiki Patel

Thank you, Marianne. This concludes our prepared remarks, and we will now start the Q&A session. Joining me for the Q&A are Marianne and Aziz. Please limit questions to 2 per person so we can get to all of our covering analysts.

I'll turn it over to you, operator.

Operator

[Operator Instructions] Your first question comes from the line of Cory Kasimov with Evercore ICI.

Question-and-Answer Session

Unknown Analyst

It's Johnny on for Cory. Regarding VIR-5500, if you could tell us about the durability of responses that you're seeing already in the current trial.

Marianne De Backer

Sorry, I did not get your name.

Unknown Analyst

Sorry, it's Johnny on for Cory.

Marianne De Backer

Okay. Great. Yes. Thank you for that question. So we are not sharing any updated information on VIR-5500 at this time. But as you have seen, we have made some really remarkable progress, the Fast Track designation by the FDA for late time and CRPC patients. And then Astellas yesterday already shared in their earnings call that we have designated the program as having achieved proof of concept. So that is a very important hurdle to prepare for our pivotal trials next year. And so in the course of next year, prior to our pivotal trials, we will be in a position to potentially share more.

Operator

Your next question comes from the line of Mike Oz with Morgan Stanley.

Avraham Novick

It's Avi Novak on the line for Mike. Congrats on all the progress. I guess as I'm sure you've seen a competitor recently shared their Phase III HDV data. So I was wondering, I guess, your thoughts -- updated thoughts on competitive positioning. Does this change the competitive bar in your view for your Phase III trial, acknowledging that there is, of course, a difference in your endpoints and how you're defining a responder.

Marianne De Backer

Yes. Thank you for that question, Avi. So as you recall, in our Phase II SOLSTICE data, we have shown to be in a possibility to achieve 60%, 60% of target not detected. So really getting rid of the virus in 66% of the patients after 48 weeks of treatment. And what you have seen from the competition, I think, for the 24-week endpoint is, I believe, a 17% target not detected. So we still believe that from an efficacy perspective and everything we have shown from the SOLSTICE data that we have the potential to be a best-in-class treatment and having shown very fast and deep antiviral efficacy.

Operator

Your next question comes from the line of Phil Nadeau with TD Cowen.

Philip Nadeau

Two from us. So you mentioned Astellas and Vir have noted that VIR-5500 achieved proof of concept. We're curious whether you'd be willing to share any of the criteria for proof of concept or even whether what categories were analyzed from response to duration to safety, things like that? That's the first question.

And then second, on HDV, we're curious what prelaunch activities you can do or you have been doing to work with payers and clinics to define reimbursement and identify patients. Any information you could share would be helpful.

Marianne De Backer

Yes. Thank you for those questions, Phil. On your first one, Astellas and ourselves have indeed designated VIR-5500 to have achieved a proof of concept. Obviously, I cannot go into the details of the criteria that we have preset to be achieved. But I can tell you it's really the combination holistically of the efficacy, the safety, the pharmacology, biomarker data that have led us to decide on the proof of concept being achieved.

And then as to your question on delta prelaunch activities. So we have actually done quite a bit of work already. We have done market research with health care professionals. We have done work related to payers. We have been looking at, of course, diagnosis and what is changing in that landscape.

What is very positive is, I think that post the launch of Hepcludex earlier this year by Gilead, that we have seen a market increase in HDV RNA testing. So we think that is a very positive evolution and will obviously help with diagnosis. And we have also looked into distribution channel, both for in-home administration and administration by a health care professional. So yes, quite a bit of prelaunch work that we have started that is ongoing.

Operator

Your next question comes from the line of Roanna Ruiz with Leerink.

Unknown Analyst

This is Anna on for Roanna. Just starting with 5500. Just curious, when you mentioned multiple pivotal trials are expected next year, can you help us narrow down which settings are maybe likely to lead and what remains outstanding before the first study can begin?

Marianne De Backer

Yes. Thank you, Anna. So we will be sharing more information on that, of course, together with our partner, Astellas. What I can tell you is, as you know, we are exploring VIR-5500 both for a late-line population, and that's where we achieved the Fast Track designation lately. But we're also exploring it both as monotherapy and combination in an early line set of patients. So obviously, we are aiming to target both early and late line, and we will be sharing more information on pivotal trial design in the course of next year.

Operator

Your next question comes from the line of Sean McCutchen with Raymond James.

Jacob Orkwis

Jacob Orkwis here on for Sean McCutchen. We're wondering here if we could grow a little bit into the market opportunity, specifically, if there are any early indicators you've seen from the Hepcludex launch in the U.S. and whether or not you've gotten any feedback on whether there's a desire to switch patients on to a more convenient therapy.

Marianne De Backer

Yes. Thank you. So I would say that one sort of leading indicator is that in our ECLIPSE-2 program, where we are looking to switch patients from bulevirtide patients that cannot get adequately controlled on bulevirtide to our elebsiran plus tobevibart regimen. As you have seen, we have had a very swift enrollment in that trial. So I think it's a bit of a leading indicator that there is really a need for this.

In addition, given sort of the black box warning associated with Hepcludex and the sort of anxiety around switching patients and potential flares, we are generating that data in the ECLIPSE-2 trial, and I think that will be very helpful for health care providers to use. So we think that the market opportunity for patients that, again, cannot be adequately controlled on bulevirtide or cannot take sort of the burden of a daily injection as a chronic treatment is an important opportunity for us.

Operator

Your next question comes from the line of Patrick Trucchio with H.C. Wainwright.

Luis Santos

This is Luis in for Patrick. I would continue on HDV. And can you clarify the FDA-agreed statistical hierarchy for the week 48 TND plus ALT endpoints versus TND alone? And I was wondering if you could also tell us a little bit about the finite treatment exploration for ECLIPSE-2 and ECLIPSE-3 and what qualifies the patient to stop, which agents withdrawn and how long they will be followed?

Marianne De Backer

Yes. Thank you, Luis. So as you know, as part of our registrational package for hepatitis delta, we have 3 trials with different endpoints. And what we have agreed with the FDA is that for ECLIPSE-1 and ECLIPSE-3, we have a 48-week endpoint. For ECLIPSE-2, we have a 24-week endpoint. And the endpoints are different.

For ECLIPSE-1, our primary endpoint is a combination of TND plus ALT at 48 weeks, and we have a secondary endpoint of TND alone. And then for ECLIPSE-2, we have, as I said, the endpoint is already at 24 weeks and it's only TND. And then also for ECLIPSE-3, the endpoint is at 48 weeks and it's only target not detected. So really getting rid of the virus viral elimination. So that is agreed, obviously, with the FDA. And obviously, we are looking forward to reporting out data on ECLIPSE-1 in the fourth quarter of this year and then for ECLIPSE-2 and ECLIPSE-3 in the first quarter of next year.

As to your question on finite treatment, we will be sharing more information on that in the future, but you are absolutely correct that as part of our ECLIPSE-2 and ECLIPSE-3 trial design, we are looking into that potential exploration.

Operator

Your next question comes from the line of Joseph Stringer with Needham.

Joseph Stringer

Just looking ahead to ECLIPSE-3, the head-to-head versus bulevirtide, what treatment delta on the TND primary endpoint do you consider the bar for success there? I guess how much better than bulevirtide does your combo therapy have to be on that endpoint for it to be considered clinically and commercially meaningful?

Marianne De Backer

Yes. Thank you for that question. So as you know, sort of the levels of target not detected or viral elimination that bulevirtide has been reporting depending on the dose is somewhere between 12% and 20% after 48 weeks of treatment. What we have shown in our SOLSTICE trial is target not detected levels, as mentioned earlier, after 48 weeks of around 66%. So I'm not going into the detail of how much differentiation you would need to see. But of course, on the viral efficacy level, there's a fundamental potential difference here.

Also, the frequency of administration. So bulevirtide is a daily injection that patients need to make chronically for the rest of their lives, given it's intended to be a treatment for chronic hepatitis delta. And in our case, it's monthly 2 injections. So I think from a convenience perspective, also this is fundamentally a very, very different regimen.

Operator

Your next question comes from the line of Etzer Darout with Barclays.

Etzer Darout

Just curious about the ECLIPSE-1 disclosure package for the top line. How much data can we expect there? Should we expect individual components like RNA undetectable and more normalization beyond the combined response endpoint? And also, could we learn anything about cirrhosis subgroup results as well as the full safety on the top line? Anything there would be helpful.

Marianne De Backer

Yes. Thank you, Etzer. Yes, for ECLIPSE-1, so as you know, we have approximately 120 patients in that trial, and we'll be reporting out data on that. We will be reporting out, obviously, on the primary endpoint, which is a combination of target not detected viral elimination combined with ALT normalization. And we will also be sharing information on secondary endpoints, to your point, cirrhosis, patients with cirrhosis and of course, safety and tolerability profile.

Operator

This concludes the Q&A session of the call. I will now turn it back to Kiki Patel, to close the call.

Kiki Patel

Thank you for joining us today and for your continued interest in Vir Biotechnology. We look forward to keeping you updated in the quarters ahead. This concludes today's call.