For the first time that immunotherapy may be used to cure patients.
An immunotherapy drug can be used to cure women of a rare type of cancer arising from pregnancy when existing treatments have failed, researchers claim in the study published in The Lancet journal.
Three out of four patients with the cancerous forms of gestational trophoblastic disease (GTD) went into remission after receiving the immunotherapy drug pembrolizumab in a clinical trial carried out by the researchers.
"We have been able to show for the first time that immunotherapy may be used to cure patients of cancerous GTD," said Michael Seckl, from the Imperial College London in the UK.
"The current treatments to tackle GTD cure most cases of the disease. However, there are a small number of women whose cancers are resistant to conventional therapies and as a result have a fatal outcome," said Seckl, lead author of the study.
"Immunotherapy may be a life-saving treatment and can be used as an alternative to the much more toxic high dose chemotherapy that is currently used," she said.
GTD is the term used to describe abnormal cells or tumours that start in the womb from cells that normally give rise to the placenta. They are extremely rare but can happen during or after pregnancy.
Globally, 18,000 women are diagnosed annually with cancerous forms of GTD, most of whom are cured with chemotherapy or surgery.
However, up to five per cent of these women's outcomes are fatal due to factors such as chemotherapy resistance and rare forms of the cancer such as placental site trophoblastic tumours (PSTT) that develop four or more years after the causative pregnancy has ended.