An antimalarial drug used in ancient Chinese medicine could be an effective treatment for polycystic ovary syndrome (PCOS), a groundbreaking study suggests.
The herbal extract artemisinin appeared to stop the ovaries producing too much testosterone, and women who took the drug for 12 weeks had more regular periods. The findings from the small trial by a Chinese team have been hailed as a potential breakthrough that could lead to an entirely new approach to treating the condition that affects around one in 10 women.
“It’s very rare that you get a brand new development in a really important condition, so this is big,” said Dr Channa Jayasena, a clinical senior lecturer at Imperial College London, who was not involved in the research. “It’s a tremendous potential breakthrough and really welcome as women’s health problems have not traditionally received the attention that heart disease and cancer have.”
PCOS occurs when the ovaries produce too much testosterone. The hormonal imbalance interferes with ovulation, which can lead to irregular periods and affect fertility. There are other wide-ranging health impacts, with many patients developing insulin resistance, which raises the risk of obesity, heart disease and diabetes. Higher testosterone levels can also cause excess facial hair and acne.
“The name [of the syndrome] makes it sounds like it just affects the ovaries, which does a disservice to women,” Jayasena said. “It’s a body-wide disease. You’re more likely to have obesity, heart disease, too much hair, acne, as well as irregular periods and fertility problems.”
Current treatments include the contraceptive pill, which suppresses testosterone production and so helps manage irregular periods and the cosmetic symptoms of PCOS. Fertility drugs or surgery can also help stimulate ovulation for women with PCOS who are unable to conceive. However, these treatments are not fully effective and are not suitable for everyone.
The latest study, published in Science, suggests artemisinin blocks an enzyme called CYP11A1 that is crucial for testosterone production in the ovaries. In a series of detailed experiments in mice and rats with a PCOS-like condition, scientists showed that the drug reduced testosterone and restored fertility. “This is an excellent tour de force of work … the results are quite dramatic,” Jayasena said.
In patients, PCOS disrupts the ovulation cycle, which normally involves follicles in the ovary maturing in a conveyor belt fashion, with one follicle selected each month to fully mature and release an egg. In PCOS, follicles are overactive, meaning lots of small follicles are maturing at once.
Prof Richard Anderson, the head of obstetrics and gynaecology at the University of Edinburgh, said: “They get in a traffic jam and instead of one going ahead to ovulate, they all remain in this state of part-development.” He said the results from the study looked “remarkably positive”.
In a pilot trial, 19 women with PCOS were given the artemisinin for 12 weeks. They had a substantial reduction in hormone levels, an ultrasound scan showed a reduction in follicle activity, and regular periods were restored in 12 of the participants (63%), with no reported negative side-effects.
Prof Qi-qun Tang, who led the research at Fudan University in Shanghai, said: “Based on our findings, artemisinins are promising candidates for treating PCOS because they strongly inhibit ovarian androgen synthesis, reduce immature follicles, and improve the [menstrual] cycle.”
The women’s periods remained regular in an extended 12-week follow up after they had stopped taking the drug. “We are now extending this observation period to determine if there is a relapse after a longer period without the drug,” said Tang, adding that the team was working to refine the dosage and timing of the medication with a view to conducting a larger clinical trial.
Anderson said: “It looks very exciting and what’s intriguing is that it’s a repurposing of a drug that’s been used for a long time. It has a big track record as a drug that humans can take safely, so that’s a fantastic hurdle to have overcome already.”
A larger trial will still be needed to assess any potential risks of taking the drug for a prolonged period. There is also a question of whether the drug restores fertility. This could be a potential advantage, but there could also be serious risks from using a hormone-suppressing drug during pregnancy. “It could be a double-edged sword if it helps you become pregnant,” Jayasena said. “Then you have to show it’s safe in pregnancy.”
