Strategic Collaboration with Astellas
Vir announced a global co-development and co-commercialization collaboration with Astellas for VIR-5500. Key terms include $315M upfront (comprised of $240M cash and $75M equity at $10.36/share), a $20M manufacturing tech-transfer milestone expected by mid-2027, up to $1.37B in additional development/regulatory/ex-U.S. commercial milestones, and total potential combined upfront and milestone payments of $1.7B. U.S. profits to be split 50/50; Vir has an option to co-promote in the U.S.; Astellas has exclusive ex-U.S. rights while Vir is entitled to tiered double-digit royalties and sales milestones; global development costs shared 40% Vir / 60% Astellas. Closing is subject to Hart-Scott-Rodino waiting period.
Compelling Phase I Efficacy Signals for VIR-5500
Phase I (cutoff Jan 9, 2026) enrolled 58 heavily pretreated mCRPC patients. At Q3-week doses ≥3,000 µg/kg (primary development focus): 11 RECIST-evaluable patients produced a 45% objective response rate (5 responders: 4 confirmed, 1 pending) and a 64% disease control rate. PSA outcomes were strong: 82% achieved PSA50, more than 50% achieved PSA90, and nearly 33% achieved PSA99 in the reported dataset. Dose-dependent antitumor activity was observed across PSA, RECIST and PSMA-PET measures.
Favorable Safety Profile and Therapeutic Window
No dose-limiting toxicities observed across dose-escalation cohorts; limited cytokine release syndrome (CRS) events predominately Grade 1 (fever) and Grade 2, with no Grade 3 CRS observed at doses ≥3,000 µg/kg. Overall, Grade ≥3 treatment-related adverse events occurred in 12% of patients and were mainly laboratory abnormalities. Prophylactic steroids or IL-6 blockade were generally not required (explored only in 3 patients at the highest 4,000 µg/kg cohort).
Durability Signals and Notable Case Studies
Several patients demonstrated durable responses with continued therapy up to 27 weeks in the dataset and illustrative case studies showing durable responses up to ~12 months, including complete resolution of multiple liver metastases and PSA99 declines in heavily pretreated patients with visceral disease.
Platform Validation (PRO-XTEN Dual Masking)
Data provide clinical validation for the PRO-XTEN dual masking approach: reduced systemic T-cell activation/CRS, ability to dose higher with less frequent administration (Q3-week preference), extended half-life via XTEN masks, and concordant tumor engagement across PSA, RECIST and PSMA-PET metrics—supporting broader pipeline potential (HER2, EGFR programs and 7 preclinical candidates).
Operational and Development Milestones
Dose escalation completed for Q1-week and Q3-week regimens; go-forward dose selected (in ~3,000–3,500 µg/kg maintenance range); transition to expansion cohorts planned for Q2 2026 (late-line mCRPC monotherapy, first-line mCRPC combination, metastatic hormone-sensitive combination); target to advance into Phase III development in 2027.
Improved Financial Discipline and Capital Position
2025 vs 2024: R&D expenses decreased to $456M from $507M, a $51M (10%) reduction; SG&A decreased to $92M from $119M, a $27M (23%) reduction. Net loss improved to $438M in 2025 from $522M in 2024 (an $84M, ~16% reduction). 2025 net change in cash and investments was approximately $314M (includes $64.3M Norgine reimbursement). Starting 2026 cash, cash equivalents and investments ~ $782M (excluding Astellas upfront/equity).
Extended Cash Runway
Including the net effects of the Norgine and Astellas agreements, Vir anticipates cash runway extending into the second quarter of 2028, enabling multiple upcoming value-creating milestones across the pipeline.