08:41 AM EST, 01/08/2025 (MT Newswires) -- Vir Biotechnology ( VIR ) said Wednesday that initial phase 1 data from two of its dual-masked T-cell engagers, VIR-5818 and VIR-5500, showed "encouraging" safety and efficacy profiles.

For VIR-5818, which targets various HER2-expressing solid tumors, data showed that half of patients getting doses of at least 400 micrograms per kilogram experienced dose-dependent tumor shrinkage across several HER2-positive tumor types, the company said.

For VIR-5500, which targets PSMA in metastatic castration-resistant prostate cancer, there were "encouraging" signs of prostate-specific antigen responses, Vir said.

The company said a promising safety profile with maximum tolerated dose has not yet been reached for VIR-5818 or VIR-5500 as dose escalation continues.

Vir shares soared over 47% in premarket activity Wednesday.

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