New drug could offer hope to eye cancer sufferers

New drug could offer hope to eye cancer sufferers

For years, experts have been attempting to develop a medication which can help to treat people suffering from eye cancer, which is particular deadly condition suffered by thousands of people across the planet.

Now, it seems that a drug commonly used to treat seizures can make eye tumours less likely to grow if they spread to other parts of the body.

A study carried out by researchers at the Washington University School of Medicine in St Louis, published online in the journal Clinical Cancer Research, suggests this new approach may be beneficial to sufferers of uveal melanoma, which is the second most common form of melanoma and can be very aggressive.

Principal investigator Dr J William Harbour, the Paul A Cibis distinguished professor of ophthalmology and visual sciences and professor of cell biology and of molecular oncology at the facility, noted that the disease can spread, or metastasize, from the eye to other organs, especially the liver.

"Melanoma in general, and uveal melanoma in particular, is notoriously difficult to treat once it has metastasized and grown in a distant organ," he explained.

"We previously identified an aggressive class 2 molecular type of uveal melanoma that, in most cases, already has metastasized by the time the eye cancer is diagnosed, even though imaging the body can"t detect it yet."

This microscopic amount of cancer can remain dormant in the liver and elsewhere for several years before it begins to grow, once this happens, the prospects for survival are poor.

However, Dr Harbour, who also directs the Center for Ocular Oncology at the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine, said that drugs known as histone deacetylase (HDAC) inhibitors can alter the conformation of the DNA of the aggressive form of uveal melanoma, which changes the way key genes are expressed, and makes the tumour cells less aggressive.

"We looked at uveal melanoma cells in the laboratory and in an animal model, and we found that HDAC inhibitors can block the growth and proliferation of tumour cells," he explained.

In tests, HDAC inhibitors appeared to reverse the aggressive molecular signature that had been identified many years ago as a marker for metastatic death.

When experts observed aggressive melanoma cells under the microscope after treatment with HDAC inhibitors, they looked more like normal cells and less like tumour cells, he stated.

Because HDAC inhibitors already are on the market, the specialist believes it may be possible to quickly begin testing the drugs in patients with aggressive forms of the disease.

So far, the drugs have demonstrated mild side-effects that are not as severe as those seen in patients undergoing chemotherapy, with one HDAC inhibitor being the anti-seizure drug valproic acid, the most common side-effect of which is drowsiness, which is typical of all HDAC inhibitors.

Clinical trials of HDAC inhibitors will be needed, as will he testing of an HDAC inhibitor called suberoylanilide hydroxic acid in patients with metastatic uveal melanoma.

Dr Harbour explained: "I think this is a reasonable place to start in the challenging effort to improve survival in patients with metastatic uveal melanoma."

He elaborated: "I suspect that the best role for HDAC inhibitors will be to slow or prevent the growth of tumour cells that have spread out of the eye but cannot yet be detected. This might lengthen the time between the original eye treatment and the appearance of detectable cancer in the liver and elsewhere." 

by Adrian Galbreth

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