Researchers hail ‘breakthrough’ drug for treating ovarian cancer

The New Daily
Jun 03, 2017, updated Jun 04, 2017

Researchers are hailing an experimental drug as a major advance in the treatment of ovarian cancer, which typically claims the lives of up to 1400 Australian women every year.

The drug, known as ONX-0801, is being described as the biggest breakthrough in the past 10 years after being shown to dramatically shrink tumours in seven of 15 test patients to take part in the world’s first clinical trial.

None of those women had responded to existing drugs and established treatment regimes, and their life expectancies were rated in months.

Even more exciting is the drug’s success among women with a genetic predisposition to the particular strain of ovarian cancer that ONX-0801 was specifically engineered to attack.

In that subgroup, of the 15 test subjects, ONX-0801 saw seven out of 10 women responding.

ONX-0801 is the first in a new class of drugs that attack cancer by mimicking folic acid in order to enter cancer cells and block a rogue molecule called thymidylate synthase.

“This is a completely new mechanism of action,” said Dr Udai Banerji, deputy director of the drug development unit at Britain’s Institute of Cancer Research and the Royal Marsden NHS Foundation Trust in London, who led the study.

Ovarian cancer cells have an abnormally large number of receptors for folic acid, called alpha folate receptors. This means these cancer cells respond particularly well to the treatment.

Dr Udai Banerjee wants to accelerate the pace of clinical trials.

In extreme late-stage patients, those beyond the help of existing treatments, ONX-0801 could be expected to add “upward of six months to patients’ lives with minimal side-effects”, Dr Banerji said.

“This is much more than anything that has been achieved in the last 10 years.”

If further clinical trials continue to achieve similar results to the those seen in the initial 15-patient study, ONX-0801 has the potential to be used in early-stage treatment where Dr Banerji believes “the impact on survival may be better”.

Because the new therapy is so specifically targeted at cancer cells, it leaves healthy cells alone. This means it does not inflict the side-effects often seen with chemotherapy, such as infections, diarrhoea, nerve damage and hair loss.

Researchers also created tests to detect the cells likely to respond particularly well to ONX-080, meaning doctors will be able identify those women who stand to gain the greatest benefit.

“It’s early days, of course, but I’m keen to see this treatment assessed in later-stage clinical trials as soon as possible,” Dr Banerji said.

The symptoms of ovarian cancer can be vague, meaning many sufferers are already in the later stages of the disease by the time they seek medical help.

Around six out of 10 women are diagnosed at the point when the cancer has already spread throughout the body and is incurable.

The Cancer Council reports that only 44 per cent of Australian women are still alive five years after their initial diagnosis.