New Drug Makes Cancer Cells Can't Hide, Tumors Shrink 30 Percent

JAKARTA - Experimental cancer drugs in the form of tablets show promising initial results. In an early phase clinical trial, a drug called GRWD5769 helps immunotherapy to recognize cancer cells that had previously "hidden" from the immune system.

According to a report by The Guardian, quoted Wednesday, June 3, the trial was conducted in the UK, France, Spain, and Australia on 83 patients with cervical, bladder, liver, bowel, lung, and head and neck cancers.

All patients had previously failed to respond to treatment. Most had even exhausted all therapeutic options when they entered the study.

The result, the tumor shrank in 26 patients. Of that number, 15 patients experienced tumor shrinkage of at least 30 percent.

This drug works by opening a kind of "invisible cloak" on cancer cells. This means that tumor cells that were previously difficult for the immune system to recognize are seen again by T cells, which are the body's defense cells that are tasked with attacking infections and diseases.

In this trial, GRWD5769 was given along with cemiplimab immunotherapy. Immunotherapy is a therapy that helps the immune system recognize and attack cancer.

So far, immunotherapy has been a major breakthrough in cancer treatment. However, this therapy fails in about two-thirds of patients because some tumors are able to evade the immune system.

The key is in an enzyme called ERAP1. Tumors can manipulate this enzyme so that T cells are not detected. GRWD5769 works by inhibiting ERAP1 so that cancer cells are again seen by the immune system.

The findings were presented at the annual meeting of the American Society of Clinical Oncology in Chicago, the world's largest cancer conference.

GRWD5769 showed an effect on the six types of cancer tested. The drug stopped the disease from progressing for at least six months in 18 percent of cervical cancer patients, 32 percent of liver cancer patients, 36 percent of bladder cancer patients, 38 percent of head and neck cancer patients, 51 percent of bowel cancer patients, and 55 percent of lung cancer patients.

The lead researcher of the study, Prof Fiona Thistlethwaite from Christie NHS Foundation Trust in Manchester, called the results impressive for a tablet-shaped drug.

"For a drug given as a tablet, this is very impressive. This is still early days, and we need further studies, but this is a new drug with a new mechanism that clearly helps immunotherapy work more effectively," Thistlethwaite told The Guardian.

The tablet was developed by Oxford-based Greywolf Therapeutics. According to researchers, the drug is well tolerated by patients. Clinical trials are still ongoing and larger studies are planned.

Thistlethwaite stressed that these results do not mean that the drug is ready for widespread use.

"There is still a lot of work to be done before this drug reaches the clinic," he said.

However, he assessed that the initial signal was strong because it appeared in several cancers that were difficult to treat and previously resistant to immunotherapy.

Still referring to The Guardian's report, Prof Stefan Symeonides of the Edinburgh Cancer Centre, the lead investigator of the clinical trial in the UK, called these initial results "interesting". He said the new immunotherapy approach was starting to show benefits for patients.

Dr Samuel Godfrey from Cancer Research UK, who was not involved in the trial, also judged the results encouraging. However, he reminded that this study is still in its early stages.

"Larger trials will be needed to determine whether this approach can provide long-term benefits for patients," said Godfrey.

These results still need to be proven through larger clinical trials. But at an early stage, researchers are seeing new opportunities to help immunotherapy work again in patients who have previously not responded to treatment.