Vir advancing global HDV preparation for Tobevibart + Elebsiran launch

Tobevibart (HBsAg mAb) + Elebsiran (siRNA)

• Timelines: Topline ECLIPSE-1 data exp Q4’26, Topline ECLIPSE-2 and ECLIPSE-3 in Q1’27, with anticipated BLA filing shortly after
• ECLIPSE-2 and Switch messaging:
  • Vir believes that ECLIPSE-2 data, in patients who switch to tob + ele after having received Hepcludex (bulevirtide) 2mg, will be important to support medication transitions, noting Hepcludex’s boxed warning regarding risk of severe acute exacerbations of Hep D and Hep B following treatment discontinuation
  • Vir noted that “no competing CHD program is expected to have comparable switch data at launch”, alluding to Mirum’s AZURE-3 switch trial (data guided for H1’28)
• HDV RNA undetectability (TND): Vir continues to emphasize increasing TND over time, highlighting Wk 96 Ph2 SOLSTICE data, presented at EASL 2026, in which 88% achieved HDV RNA TND in ITT analysis, and 97% when using “last observation carried forward” analysis
• Dosing and Admin:
  • Vir had a productive Type B CMC meeting with FDA, and is currently conducting human factor studies to bridge to at-home administration (since tob + ele was administered in hospital setting in ECLIPSE trials)
  • Vir is also pursuing co-packaging of tob + ele in US to make it more convenient for patients to self-admin
• Manufacturing: Drug substance process performance qualification (PPQ) manufacturing activity is complete for both tob + ele; drug product PPQ batches are in progress
• Ex-US plans:
  • Vir is well-positioned to support broad regulatory submissions globally
  • Launch prep activities are underway across EU, Australia, and New Zealand, with Norgine responsible for commercialization of tob + ele in these geographies, if approved

The Ph3 ECLIPSE 2 (N=150; PCD: Dec 2026) trial completed patient enrollment in Q2 2026 

Management expects ECLIPSE 2 to demonstrate high rates of undetectable HDV RNA after switching patients from bulevirtide to the combination regimen 

Vir expects strong physician adoption due to tobevibart + elebsiran’s strong efficacy profile, and also cited bulevirtide's boxed warning regarding the risk of severe acute exacerbations of HDV and HBV post-treatment discontinuation 

Management added other competitors are expected to lack the comprehensive switch data at launch that Vir will possess 

Management emphasized its commercial readiness, noting it held a productive Type B CMC meeting with the FDA in Jul 2026 among other interactions facilitated through tobevibart + elebsiran’s Breakthrough Therapy Designation  

Vir is currently conducting a human-factor study with the intention of supporting at-home administration, for improved patient convenience and access 

The company did not comment on whether it expects to offer at-home administration of the combo at launch (Vir suggested it would during its Q1 2026 earnings call)  

On the topic of manufacturing readiness, Vir indicated it has completed drug substance process performance qualification (PPQ) manufacturing activities for both tobevibart and elebsiran; Drug product PPQ batches are progressing as planned 

Vir noted that, following the Norgine license agreement, launch preparation activities are underway across Europe, Australia, and New Zealand, with Norgine responsible for commercialization of tobevibart + elebsiran in these territories if approved 

Topline Ph3 ECLIPSE 1 (N=120; PCD: Dec 2026) data remain expected in Q4 2026, followed by Ph3 ECLIPSE 2 and Ph2b ECLIPSE 3 (N=100; PCD: Nov 2026) readouts in Q1 2027 

The company has extensively planned its BLA preparation process, planning to commence filing activities immediately after receiving Phase 3 ECLIPSE data 

Management summarized the 96-week SOLSTICE data presented at EASL 2026, reiterating high rates of undetectable HDV RNA, greater HBsAg reduction versus monotherapy, durable ALT normalization, and a favorable safety profile 

Management noted growing recognition of target not detected (TND) as a key HDV endpoint, pointing to the FDA’s acceptance of ECLIPSE 2's TND-only primary endpoint 

Vir emphasized that advisory board experts consistently identified TND HDV RNA as the gold standard endpoint and most meaningful measure of disease control 

When asked about potential pricing for its combo therapy, Vir management quoted bulevirtide's ~$283,000 USD price as a benchmark  

Vir noted it intends to co-package tobevibart + elebsiran in the US to simplify treatment administration and potentially enhance differentiation and adoption (did not guide to EU packaging plans) 

Vir continues to note in-office administration of tobevibart + elebsiran is likely to appeal to the ~20% of CHD patients who cannot self-administer 

Management noted upcoming AASLD guideline updates expected to promote double reflex HDV testing will improve disease awareness, streamline diagnosis, and expand patient identification to support greater uptake of HDV therapies 

It was estimated only 10-15% of US CHD patients are currently diagnosed; diagnosis rates could increase to >25% as disease awareness, testing practices, and reimbursement improve 

• Re: how quickly new patients can be identified and diagnosed in HDV: Vir cited KOLs who anticipate incorporation of double reflex testing into AASLD guidelines. They commented that major sites in California are already implementing universal reflext testing for delta, and some KOLs are re-screening patients in their HBV registry for HDV

sources: Press Release, August Corporate Presentation