New drug cocktail could double treatments for rare form of ovarian cancer

Christine Cull, pictured with her husband Dave, was diagnosed with LGSOC in 2009. She has been declared cancer-free after taking the novel drug cocktail
Christine Cull, pictured with her husband Dave, was diagnosed with LGSOC in 2009. She has been declared cancer-free after taking the novel drug cocktail

A cocktail of two drugs could offer twice as many women suffering with a rare form of ovarian cancer hope of treatment, according to a new study.

Currently, only a quarter (26 per cent) of women diagnosed with a type of ovarian cancer called low-grade serous ovarian cancer (LGSOC) will respond to the best available treatment.

However, a study from Royal Marsden Hospital’s cancer experts has found that a course of two drugs together has a response rate of almost half (45 per cent). It is hoped that the discovery will double the number of patients who can be treated for the disease.

LGSOC is an uncommon form of the condition and makes up around one in 10 of all ovarian cancer cases.

More likely to affect younger women

Around 700 women a year will be diagnosed with LGSCO every year in the UK and it is more likely to affect younger women than other forms of ovarian cancer.

The global study, presented this week at the American Society of Clinical Oncology annual conference in Chicago, involved a total of 121 patients.

A total of 59 were enrolled in the branch of the phase two clinical trial dedicated to assessing the drug cocktail’s effectiveness, with 29 getting the experimental pairing.

The new treatment involves administering both avutometinib and defactinib, two drugs which are designed to stop cancer cells growing. However, avutometinib has previously been shown to have a low success rate on its own of around 10 per cent as the cancer evolves resistance and circumvents the drug.

Effective combination

Marsden oncologists hoped that pairing it with defactinib, a drug known to stop cancers from accruing such resistance, would boost effectiveness.

The combination of the two was four times as effective as avutometinib alone, and twice as effective as the current best treatment option, a drug called trametinib.

Six in 10 patients on the drug who also have a mutation in a gene called KRAS responded to the drug dyad. Three in 10 (29 per cent) of those without the mutation also saw tumour shrinkage, an improvement on existing options.

Data suggests that patients on this treatment will live for two years after starting the cocktail.

Could be ‘significant breakthrough’

Dr Susana Banerjee, consultant medical oncologist and lead author of the global study at the Royal Marsden NHS Foundation Trust Gynaecology Unit and team leader in women’s cancers at the Institute of Cancer Research, London, said the results “could be fantastic news for women” and indicates a “far more effective treatment could be on the horizon”.

“It’s wonderful to see so many patients experience a meaningful response to this innovative drug combination and I’m so grateful to all who joined the trial, making this research possible,” she said.

“Low-grade serous ovarian cancer does not respond well to currently approved treatments, so these results could represent a significant breakthrough in treating the disease.

“We are hopeful this drug combination will one day become a standard of care for women with low grade serous ovarian cancer.”

Dr Catherine Elliott, director of research and partnerships at Cancer Research UK, said: “It’s encouraging to see progress in therapies for this type of ovarian cancer, which is often hard to treat.

‌“Studies like this can help us better understand how treatments can be targeted based on mutational signatures in cancers, and the results from this research are promising.

“We look forward to seeing the next steps of this research on a much larger scale, in order to uncover how this treatment could affect not just tumour shrinkage, but long-term survival too.”

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