Shares of Vir Biotechnology, Inc. (VIR) surged more than 50% in overnight trading after the company announced a global strategic collaboration with Astellas Pharma for its PSMA-targeting T-cell engager, VIR-5500, and released updated Phase 1 clinical data showing encouraging results.
According to the global strategic collaboration, Astellas and Vir Biotechnology will co-develop and co-commercialize VIR-5500, an investigational PRO-XTEN dual-masked T-cell engager designed to target PSMA in metastatic prostate cancer, sharing both development costs and future revenues.
Under the terms of the agreement, Vir will receive $335 million in upfront and near-term payments, including $240 million in cash, a $75 million equity investment at a 50% premium, and a near-term $20 million milestone payment. The company is also eligible for up to an additional $1.37 billion in development, regulatory, and sales milestones, along with tiered, double-digit royalties on ex-U.S. net sales.
Astellas will lead U.S. commercialization, with Vir retaining an option to co-promote. Outside the U.S., Astellas will hold exclusive rights. Development costs will be shared, with Astellas covering 60% and Vir 40%.
The updated Phase 1 results for VIR-5500 monotherapy in heavily pre-treated metastatic castration-resistant prostate cancer show a favourable safety and tolerability profile, along with early indications of durable anti-tumour activity.
Key findings include:
•No dose-limiting toxicities observed to date.
•82% PSA50 and 53% PSA90 declines in higher-dose cohorts.
•45% objective response rate among RECIST-evaluable patients.
•Favorable tolerability with events generally restricted to Grade 1 (fever only).
The company has completed monotherapy dose-escalation and defined a go-forward dose for expansion. Dose-expansion cohorts in late-line mCRPC and combination cohorts with enzalutamide in earlier-line settings are expected to begin in Q2 2026, with pivotal Phase 3 trials planned for 2027.
Beyond VIR-5500, Vir's broader pipeline includes:
•Chronic Hepatitis Delta (CHD): The company advanced its combination of Tobevibart and Elebsiran, supported by strong Phase 2 SOLSTICE data showing 88% HDV RNA undetectable rates at Week 96. Multiple Phase 3 ECLIPSE trials are underway, with topline data expected between Q4 2026 and Q1 2027.
•Oncology Portfolio: Additional PRO-XTEN masked TCEs- VIR-5818 (HER2) and VIR-5525 (EGFR)- continue in Phase 1 dose-escalation, with response data for VIR-5818 anticipated in 2H 2026.
Vir ended 2025 with $781.6 million in cash, cash equivalents, and investments, reflecting disciplined spending and restructuring benefits.
The company expects its current cash position, inclusive of the Astellas collaboration, to fund operations into the second quarter of 2028.
VIR has traded between $4.16 and $9.84 over the past year. The stock closed Monday's trading at $7.43, down 1.72%. In the overnight trading session, the stock rose to $11.45, up 54.10%.
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Business News
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