Experimental drug exposes hidden cancer cells to the immune system

An experimental cancer drug designed to prevent tumour cells from evading the immune system has shown encouraging results in an early-stage international clinical trial involving patients with six common types of cancer.

The drug, GRWD5769, was developed by Greywolf Therapeutics and tested in combination with the immunotherapy treatment Cemiplimab.

Researchers reported that tumours shrank in 26 of 83 patients enrolled in the study, with 15 patients experiencing tumour reductions of at least 30%.

The phase 1 trial included patients with cervical, bladder, liver, bowel, lung, and head and neck cancers across the UK, France, Spain, and Australia. All participants had cancers that had failed to respond to previous treatments, including immunotherapy.

Researchers said the drug works by inhibiting an enzyme known as ERAP1, which some cancer cells use to avoid detection by the immune system. By blocking the enzyme, GRWD5769 makes tumour cells visible to T-cells, enabling immunotherapy to target and destroy them more effectively.

The study found that the disease did not progress for at least six months in 18% of cervical cancer patients, 32% of liver cancer patients, 36% of bladder cancer patients, 38% of head and neck cancer patients, 51% of bowel cancer patients, and 55% of lung cancer patients.

The findings were presented at the annual meeting of the American Society of Clinical Oncology in Chicago.

The trial's principal investigator, Fiona Thistlethwaite, said the results were impressive for a tablet-based treatment and noted that the drug appeared to improve the effectiveness of immunotherapy with relatively few side effects.

Researchers cautioned that the trial remains in its early stages and that larger studies will be required to determine whether the treatment can provide long-term benefits. A larger follow-up trial is already being planned.