Investing.com -- Shares of Vir Biotechnology, Inc. (NASDAQ:VIR) surged 29% following the release of encouraging safety and efficacy data from ongoing dose escalation trials for its dual-masked T-cell engagers, VIR-5818 in solid tumors and VIR-5500 in metastatic castration-resistant prostate cancer (mCRPC).
The San Francisco-based biotechnology firm presented initial Phase 1 data indicating that its candidates, VIR-5818 and VIR-5500, show promising preliminary safety and efficacy profiles. The trials have not reached the maximum tolerated dose, suggesting a favorable safety margin, and no dose-limiting cytokine release syndrome has been observed. Early clinical response signals were seen in heavily pretreated patients, with VIR-5818 demonstrating tumor shrinkage in 50% of participants with various HER2-expressing cancers at doses ≥400 µg/kg. Moreover, confirmed partial responses were observed in 33% of participants with HER2-positive colorectal cancer.
VIR-5500 also showed positive signs, with all participants experiencing prostate-specific antigen declines after an initial dose ≥120 µg/kg, and 58% achieving a PSA50 response at this dosing level.
The company’s CEO, Marianne De Backer, expressed optimism about the potential of these treatments to provide efficacious and well-tolerated options for cancer patients, highlighting the innovative PRO-XTEN™ masking technology that allows for selective activation of the T-cell engagers in the tumor microenvironment, thereby minimizing damage to healthy tissue.
VIR-5818, a potential first-in-class HER2 immunotherapy, is being evaluated in combination with pembrolizumab for a range of HER2-expressing cancers, including breast and colorectal cancer. VIR-5500 targets PSMA in mCRPC, addressing the need for treatments that can extend survival and improve the quality of life in prostate cancer, the second most diagnosed cancer in men.
The promising data from these early-stage trials have clearly resonated with investors, as reflected in the significant rise in Vir Biotechnology’s stock price. The company plans to continue dose escalation in these trials and is evaluating less frequent dosing regimens based on the half-life of the T-cell engagers.
Vir Biotechnology is set to discuss these findings in an investor conference call on January 8, 2025, further details of which can be found on their investor relations website.
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