New Prostate Cancer Drug Shrinks Tumors in Half of Patients

Men with advanced prostate cancer now have something they've been waiting years for: an immunotherapy that actually works.

In a remarkable trial, 45% of patients saw their tumors shrink after receiving VIR-5500, a new drug that uses the body's immune system to fight cancer. Until now, immunotherapy had largely failed prostate cancer patients, either showing little effect or causing severe side effects.

The Institute of Cancer Research and the Royal Marsden NHS Foundation Trust led the study of 58 men whose cancer had stopped responding to all other treatments. These were patients facing the toughest battles, yet the new approach gave many of them real results.

The drug works like a guided missile for cancer cells. It binds to the body's immune T-cells and links them directly to prostate cancer cells, enabling a targeted attack wherever the cancer has spread.

What makes VIR-5500 different is its built-in "cloaking device" that keeps it inactive until it reaches the tumor. This innovation prevents the drug from triggering immune responses throughout the body, which explains why 88% of patients experienced only mild side effects.

The results were even more striking at higher doses. Half of the 17 patients receiving the maximum dose saw their PSA levels drop by 90%. PSA is a blood marker that indicates prostate disease, and such dramatic drops suggest the treatment is genuinely working.

Prostate cancer affects 55,000 British men every year, making it the most common cancer in men. High-profile patients like Olympic champion Sir Chris Hoy, 49, have brought attention to the disease and the urgent need for better treatments.

Why This Inspires

This breakthrough represents decades of research finally paying off for a patient group that desperately needed new options. Professor Johann de Bono, who led the study, says the drug will now move to larger trials with the goal of making advanced prostate cancer curable, even after it has spread.

The trial recruited patients from eight sites worldwide, and the results were presented at the American Society of Clinical Oncology Genitourinary Cancers Symposium in San Francisco. Vir Biotechnology funded the research.

For men who thought they'd exhausted all options, this treatment offers something precious: hope grounded in real science and real results.