A new wonder pill has been described as a ‘major breakthrough’ in treating one of the deadliest forms of ovarian cancer, dubbed the ‘silent killer’.
The number of British patients whose tumours shrank was over four times higher compared to those receiving standard therapies.
The pioneering drug, taken daily, almost halved the speed of relapse – more than doubling their chance of long term survival.
There will be no further trials – and it may now be used in the clinic, say the Scottish team.
Study leader Professor Charlie Gourley described it as a “major breakthrough that paves the way for better outcomes”, adding It may have “further uses going forward”.
It was used to target ‘low grade serous ovarian cancer’, also known as LGSOC, a relatively rare form of the disease that responds poorly to treatment.
The global study involved 260 patients in the UK and the US, many of whom were under 40, who were followed for an average of two and a half years.
Half were given the tablet, called trametinib, which was originally developed to combat melanoma, the most deadly form of skin cancer.
The others received one of five standard treatments – either the hormonal drugs letrozole or tamoxifen or chemotherapy known as paclitaxel, PLD (pegylated liposomal doxorubicin) and topotecan.
Professor Charlie Gourley, director of ovarian cancer research at the University of Edinburgh, which ran the British arm of the international trial, said: “Low grade serous ovarian cancer is different from other ovarian cancers because it affects younger women and is often resistant to chemotherapy.
“This is the first positive, randomised trial in this disease and represents a major breakthrough for patients with this type of ovarian cancer.”
Around 7,500 women are diagnosed with ovarian cancer every year in the UK. Low grade serous ovarian cancer accounts for up to one in ten cases.
The tumours are often slow growing, and usually detected in women under the age of 45.
Ovarian cancer has one of the worst survival rates, so better treatments are desperately needed. It claims around 4,200 lives, annually.
It has been dubbed the ‘silent killer’ as there are few symptoms, so by the time it is caught treatment options are often limited.
Just 35 per cent of patients live 10 years or more after their diagnosis. Even when surgery and chemotherapy has appeared to work, around 70 per cent go on to relapse within three years.
Prof Gourley said: “The trial was performed in the USA and the UK. The drug has been shown to have efficacy in this rare form of ovarian cancer, but is also used for melanoma.
“It paves the way for better outcomes. It may well turn out to have other uses going forward.
“Even though this form of ovarian cancer is rare, it has few specific treatment options and has been under-researched. That is why it is so important to have something to offer these women.”
He added: “Until now low grade serous ovarian cancer has been particularly difficult to treat.”
Patients are normally given surgery and chemotherapy. Most show no evidence of disease afterwards – but around 70 per cent will relapse within three years.
Ovarian cancer is typically incurable once it returns. Patients go on to receive several types of treatment but, over time, the interval between relapses becomes progressively shorter.
Prof Gourley’s team, working with colleagues at the University of Texas’ MD Anderson Cancer Centre, assigned the participants at random to a daily dose of trametinib or their doctor’s choice of the other currently available drugs.
Trametinib belongs to a class of drugs known as MEK inhibitors. They work by blocking a very important signal that controls the growth of cancer cells, causing them to multiply in an uncontrolled fashion.
The researchers said: “Patients who received trametinib showed a chance of progression-free survival that was more than double that of those who received standard of care treatment.
“The percentage of patients whose tumour shrank was more than four times higher in trametinib patients compared to those treated with the standard of care.
The study, presented at the European Society for Medical Oncology (ESMO) Congress 2019 in Barcelona, was supported by the National Cancer Institute and Cancer Research UK.
Prof Gourley said: “This study will not be repeated, it was already big at 260 patients. We are discussing with the drug company, Novartis, whether they will apply for a license on the basis of these data. This would be required before the drug could be used in the clinic.”
