A drug which is being investigated as treatment for a rare disease could extend the lives of patients with an aggressive form of ovarian cancer, according to a clinical trial.

Platinum-resistant ovarian cancer occurs when the disease progresses within six months of starting platinum-based chemotherapy. This form of chemotherapy is different from other types because it uses compounds that contain platinum to destroy cancer cells by preventing them from dividing.

On average, patients with ovarian cancer that is resistant to this type of chemotherapy are typically expected to survive for only a year after diagnosis, and their treatment options are limited.

A study published in the Lancet analysed data from 381 patients with platinum-resistant ovarian cancer. Participants received either usual treatment or relacorilant, a pill investigated as a possible treatment for Cushing’s syndrome, a condition caused by excessive levels of the hormone cortisol.

After an average follow-up of two years, the results showed a 35% reduction in the risk of death among patients treated with relacorilant compared with those receiving usual care. On average, patients in the relacorilant group lived four months longer than those in the control group.

The researchers concluded that these findings supported relacorilant as a potential new standard treatment option for patients with platinum-resistant ovarian cancer.

A separate study involving 643 platinum-resistant ovarian cancer patients found those treated with pembrolizumab alongside usual care lived for an average of 17.7 months, while those who had usual care alone survived for an average of 14 months. Pembrolizumab is an immunotherapy drug that works by stimulating the immune system to attack cancer cells.

Ovarian cancer is the sixth most common cancer among women in the UK, with about 7,600 cases diagnosed each year. It accounts for about 4% of all new cancer cases among women, and there are about 3,900 deaths annually.

Both trials are at phase 3 and require further testing before they can be approved in the UK. However, relacorilant and pembrolizumab have been approved in the US by the Food and Drug Administration for the treatment of platinum-resistant ovarian cancer.