A new immunotherapy drug for advanced prostate cancer has shown 'remarkable' results in an early-stage trial, according to experts. The treatment, VIR-5500, harnesses the body's immune system to shrink tumours or halt their growth, with minimal side-effects.
Presented at the ASCO Genitourinary Cancers Symposium, the phase 1 trial involved 58 men with advanced prostate cancer that had stopped responding to other treatments. Among 11 patients evaluated at the highest dose, 45% saw their tumours shrink. Additionally, 88% of all patients experienced only very mild side-effects.
Of 17 patients given the highest dose, 53% saw their prostate-specific antigen (PSA) levels drop by 90%, and 82% saw levels halved. The drug, a T-cell engager, uses a 'cloaking device' to remain inactive until it reaches cancer cells, reducing side-effects and allowing longer circulation in the bloodstream.
Notable cases included a 63-year-old man with 14 cancerous liver lesions that completely resolved after six cycles, and a 70-year-old whose additional small tumours disappeared. A 77-year-old patient had undetectable PSA levels after 17 cycles. Professor Johann de Bono of the Institute of Cancer Research, London, described the results as 'really remarkable' and expressed hope for future cures.
