Drugs used against ovarian cancer offer hope in tackling other forms of disease

Nilima Marshall, PA Science Reporter
·2-min read

A class of drugs used against ovarian and breast cancers may also be effective for other forms of the disease which currently have limited treatment options, according to scientists.

A new study suggests these medicines, known as PARP inhibitors, are able to kill cancer cells which harbour a defect in a gene known as PBRM1 by destroying their DNA defences.

This mutation is also found in around half of all kidney cancer cases as well as in some lung or bile duct cancers.

The faulty gene is also seen in mesothelioma, a type of cancer linked to asbestos exposure.

While defects involving the PBRM1 gene are common, the researchers say there are currently no treatments that target them.

In their findings, published in the journal Cancer Research, the experts said PARP inhibitors could offer a new approach for treating these types of cancers.

Study co-leader Dr Sophie Postel-Vinay, at Gustave Roussy in Paris, said: “PBRM1 defects occur frequently on several cancer types, and have for long been ignored because we had no technology that allowed to look for them and diagnose them in the clinical practice, until recently.

“Our findings open novel perspectives for the treatment of these cancers for which there are currently limited treatment options.”

In their study, the researchers found that cancer cells lacking the PBRM1 protein had higher than usual levels of DNA damage, which worsened when treated with PARP inhibitors.

They discovered that treating cancer cells which had PBRM1 defects with PARP inhibitors – such as rucaparib, olaparib or talazoparib – in the lab caused the cells to die.

The researchers said that exposing PBRM1-defective cancer cells to these drugs also activated the body’s anti-cancer immune response, “potentially opening opportunities for keeping cancer patients alive for longer”.

Based on their findings, some of the scientists are now putting in place clinical trials looking at combining a PARP inhibitor with immunotherapy in patients with cancers involving faulty PBRM1 genes, including kidney, lung, bladder and bile duct cancers.

Study co-leader Chris Lord, professor of cancer genomics at the Institute of Cancer Research, London, said: “Defects in the PBRM1 gene are common in various cancers, including half of all clear cell renal cell carcinomas, a common form of kidney cancer.

“Our findings suggest that cancers with faulty PBRM1 genes are sensitive to PARP inhibitors – drugs that strip cancer of its DNA defences.

“These findings are promising and our colleagues in Paris have already begun trials in patients based on this work.

“We’re hopeful that this could become a brand new genetically-targeted approach to treating cancer, and could offer hope to patients with various cancer types including a common form of kidney cancer.”