Vir Biotechnology (VIR) has announced promising initial Phase 1 data for its dual-masked T-cell engagers (TCEs), VIR-5818 and VIR-5500, leading to an upgrade of the company's stock by Morgan Stanley. The early results indicate a favorable safety profile and encouraging signs of efficacy in heavily pretreated patients with solid tumors and metastatic castration-resistant prostate cancer (mCRPC).
Early Clinical Data
VIR-5818, designed to target HER2-expressing solid tumors, demonstrated dose-dependent tumor shrinkage in 50% (10/20) of participants receiving doses ≥400 µg/kg across various HER2-positive tumor types. VIR-5500, targeting PSMA in mCRPC, showed a 58% PSA50 response rate among heavily pretreated participants, indicating a significant reduction in prostate-specific antigen levels.
The data revealed no dose-limiting cytokine release syndrome (CRS), and the maximum tolerated dose has not yet been reached, allowing for continued dose escalation. This is particularly significant as CRS, an overreaction of the immune system, can cause severe inflammation and limit the tolerability of T-cell engaging therapies.
Analyst Perspective
Morgan Stanley analyst Michael E. Ulz upgraded Vir Biotechnology from Equal-weight to Overweight, raising the price target to $20 from $10. Ulz noted that the initial data provide "early platform de-risking" and sees potential for activity to improve as dose escalation continues. He also highlighted the manageable safety profiles of both programs, suggesting a wide therapeutic index supportive of continued dose escalation and less frequent dosing.
According to Ulz, the observed response rate of approximately 33% with VIR-5818 is adequate to accelerate development. The analyst is optimistic about the early results, citing promising activity and manageable safety in both programs and is awaiting data from higher doses to confirm safety and see stronger effectiveness.
Implications for Cancer Treatment
The dual-masking technology employed by Vir Biotechnology aims to enhance therapeutic tolerability and efficacy, potentially making these treatments more acceptable for use in earlier stages of cancer treatment. This approach could address a significant unmet need in oncology by providing more effective and less toxic therapies.
Financial Outlook
Morgan Stanley's updated model now includes VIR-5500 revenue projections for prostate cancer and slightly lower operating expenses based on revised cash guidance. The company's extended cash runway to mid-2027 enhances its ability to fund ongoing clinical trials and explore strategic partnerships, according to analysts.
This upgrade reflects Vir's strategic shift beyond its traditional infectious disease portfolio into oncology, focusing on innovative cancer treatments with high potential.
