Astellas and Vir Biotechnology Enter Global Strategic Collaboration to Advance VIR-5500 for Prostate Cancer Treatment

Key Points for Investors

• Major Collaboration: Astellas Pharma Inc. and Vir Biotechnology, Inc. have announced a global strategic collaboration to co-develop and co-commercialize VIR-5500, an investigational PRO-XTEN^® dual-masked T-cell engager (TCE) targeting PSMA for advanced prostate cancer.
• Significant Upfront and Near-term Payments: Vir Biotechnology will receive \$335 million in upfront and near-term milestone payments, including \$240 million in cash, \$75 million in equity investment at a 50% premium, and a \$20 million near-term milestone.
• Potential for Substantial Milestone Payments and Royalties: Vir Biotechnology is eligible for up to an additional \$1.37 billion in development, regulatory, and sales milestones, plus tiered, double-digit royalties on ex-U.S. net sales.
• Shared U.S. Economics: The two companies will split U.S. profit/loss equally (50/50). Astellas will lead commercialization in the U.S., with Vir Biotechnology retaining the option to co-promote. Astellas will have exclusive rights to commercialize VIR-5500 outside the U.S.
• Development Cost Sharing: Global development costs for VIR-5500 will be shared, with Astellas covering 60% and Vir Biotechnology 40%.
• Clinical Progress: VIR-5500 is currently in Phase 1 development (NCT05997615) for advanced, metastatic prostate cancer. Updated Phase 1 data will be presented at the 2026 ASCO Genitourinary Cancers Symposium.
• Strategic Rationale: The collaboration aims to accelerate the development of VIR-5500 and strengthen Astellas’ oncology pipeline and leadership in prostate cancer. The program leverages Vir’s PRO-XTEN^® platform, which may have broad potential across multiple solid tumor indications.

Details Shareholders and Investors Should Note

• Equity Investment at Premium: The \$75 million equity investment by Astellas comes at a 50% premium to Vir Biotechnology’s 30-day volume weighted average share price (as of February 19, 2026), a strong indicator of Astellas’ confidence in Vir and the VIR-5500 asset.
• Milestone and Royalty Structure: The financial structure provides strong ongoing incentives for Vir Biotechnology, with sizeable potential milestone payments and royalty streams that could meaningfully impact future revenues and earnings.
• Risk Sharing: The equal U.S. profit/loss sharing and joint development cost-sharing create a partnership with aligned interests, distributing both upside and risk.
• Regulatory Impact: Closing of the transaction is contingent on customary closing conditions, including U.S. Hart-Scott-Rodino (HSR) Act clearance. Any delay or issue here could impact both companies’ near-term financial outlooks.
• Existing Licensing Obligations: A portion of certain collaboration proceeds will be shared with Sanofi under Vir Biotechnology’s licensing agreement, which may affect net proceeds to Vir.
• Potential Share Price Impact: The magnitude of upfront payments, premium equity investment, and future milestone/royalty opportunities are material and may move share prices for both Vir Biotechnology and Astellas. The development progress of VIR-5500, especially positive clinical data, could further impact valuation.

About VIR-5500 and Market Opportunity

VIR-5500 is a dual-masked, bispecific Prostate-Specific Membrane Antigen (PSMA) and CD3 binding T-cell engager, leveraging the PRO-XTEN^® masking technology. This approach is designed to keep the TCEs inactive until they reach the tumor microenvironment, potentially reducing off-target effects and improving the therapeutic index compared to existing T-cell engagers.

Prostate cancer, particularly metastatic castration-resistant prostate cancer (mCRPC), remains difficult to treat and has a 5-year survival rate of approximately 30%. Patients progressing to mCRPC face therapeutic resistance and limited treatment options, highlighting the unmet need and significant market opportunity should VIR-5500 prove successful.

Management Commentary

Adam Pearson, Chief Strategy Officer, Astellas: Emphasized Astellas’ commitment to prostate cancer, having helped 1.5 million patients, and highlighted that the collaboration strengthens Astellas’ oncology pipeline.

Marianne De Backer, CEO, Vir Biotechnology: Stated that Astellas is an “ideal collaborator” due to its strong track record in oncology and strategic alliances. She believes this collaboration validates the PRO-XTEN^® platform and enables rapid advancement of VIR-5500.

Additional Corporate Information

• A live webcast featuring the latest VIR-5500 Phase 1 data and executive commentary will be held on February 23, 2026, and the data will also be presented at the 2026 ASCO Genitourinary Cancers Symposium.
• Vir Biotechnology’s clinical portfolio includes additional PRO-XTEN^® dual-masked T-cell engagers across solid tumor indications, as well as programs for infectious diseases.
• Vir Biotechnology retains exclusive rights to the PRO-XTEN^® masking platform for oncology and infectious disease. PRO-XTEN^® is a trademark of Amunix Pharmaceuticals, a Sanofi company.

Forward-Looking Statements and Risks

• Both companies caution that forward-looking statements are subject to risks and uncertainties, including but not limited to regulatory approvals, clinical trial outcomes, development costs, competitive dynamics, and potential delays or hurdles in development or commercialization.
• Success in early-stage clinical trials does not guarantee regulatory approval or commercial success. Investors should note the high-risk nature of drug development, especially for early-stage assets.

Contact Information

• Astellas Pharma Inc.: Lisa Qu, R&D Communications (+1 443-467-0614, [email protected]); Corporate Communications (+81-3-3244-3201)
• Vir Biotechnology: Caren Scannell, Director, Communications ([email protected]); Kiki Patel, Head of Investor Relations ([email protected])

Disclaimer: This article is for informational purposes only and does not constitute investment advice. Forward-looking statements are subject to risks and uncertainties. Investors should review company filings and consult professional advisors before making investment decisions.

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