A new immunotherapy drug has produced striking early results in men with advanced prostate cancer.
Researchers reported tumour shrinkage and strong biological responses in some patients.
Prostate cancer remains the most common cancer in men in many countries.
About 1.5 million men receive a diagnosis worldwide each year.
The treatment, called VIR-5500, activates the body’s own immune system.
It links killer T-cells directly to cancer cells.
This approach helps the immune system destroy tumours that usually evade detection.
Scientists designed the drug to switch on mainly inside the tumour.
This feature reduces harmful inflammation and limits side effects.
It also allows the medicine to stay longer in the bloodstream.
The phase one trial included 58 men with advanced disease.
All participants had stopped responding to standard therapies.
Most patients experienced only mild side effects.
Researchers measured prostate-specific antigen levels to track response.
Among patients receiving the highest dose, many showed dramatic declines.
More than half recorded a reduction of at least 90%.
Some saw their PSA levels fall by almost 100%.
Tumour scans also showed clear improvements.
Five of eleven men at the top dose had measurable tumour shrinkage.
One patient with liver metastases saw multiple lesions disappear completely.
Scientists described the findings as unprecedented for prostate cancer.
The disease has long resisted immunotherapy treatments.
Experts say larger and more diverse trials are now essential.
They hope the therapy could extend survival and eventually lead to cures.
Researchers presented the data at a major oncology conference.
