A modified version of niclosamide, a decades-old tapeworm drug, shrank endometriosis lesions and eased pain sensitivity in mice, researchers at Washington State University report. Any treatment is at least five years from patients, but existing guidance already sets out how women can get symptoms recognised and treated.
In the US state of Washington, a team at Washington State University’s veterinary college has been testing an old tapeworm drug against endometriosis. Kanako Hayashi, a professor in the college’s School of Molecular Biosciences, leads the group.
Their modified form of niclosamide reduced endometriosis lesions and pain sensitivity in mice, in work published in Advanced Healthcare Materials. Endometriosis is a condition in which tissue similar to the lining of the womb grows outside it. It can cause severe pelvic pain, heavy periods, fatigue and infertility.
A drug carried into immune cells
The team targeted immune cells called macrophages, which appear to help endometriosis lesions survive. These cells carry a surface protein that binds folic acid.
The researchers attached niclosamide to a tiny branching carrier molecule coated with folic acid, according to ScienceAlert. The design is intended to carry the drug into the target cells and release it only once inside. Niclosamide on its own dissolves poorly in water, and little reaches the bloodstream when swallowed. Hayashi expects the targeted approach to reduce side effects. “Definitely side effects will be lower,” she told KUOW.
Fewer lesions in eight-mouse groups
Two weeks after a single injection, treated mice had fewer and smaller lesions than untreated mice. No lesions were found in four of eight mice given the lower dose and five of eight given the higher dose. Both doses reduced pain-related sensitivity in the abdomen and hind paws.
Each group contained eight mice, and follow-up lasted two weeks. Results in mice often fail to carry over to people. “Our study is still in preclinical stages,” Hayashi told ScienceAlert, adding that the treatment “is still a long way from being commercialized”. Several authors have disclosed pending patents on the carrier technology.
Getting symptoms recognised and treated now
Endometriosis affects an estimated 10% of reproductive-age women worldwide, about 190 million people, according to the World Health Organization. WHO states there is currently no cure, but symptoms can be treated with medicines or, for some women, surgery.
WHO says a clinical diagnosis may be made from a woman’s symptoms and imaging such as ultrasound or MRI. Surgery “is not necessarily required before initiating treatment”, it adds. Options include anti-inflammatory painkillers, hormonal medicines and multidisciplinary pain care such as physiotherapy and cognitive behavioural therapy.
In England, NICE guidance tells clinicians to suspect endometriosis in women and girls with chronic pelvic pain or period pain that affects daily life. Deep pain during or after sex, and painful bowel movements or urination linked to periods, are also on its list. NICE says women should be told that “keeping a pain and symptom diary can aid discussions”.
If symptoms persist, NICE advises clinicians to consider referral for further assessment. It also asks them to tell women about local support groups, online forums and national charities. WHO reports that many low- and middle-income countries lack the specialist teams and equipment needed for early diagnosis.
Hayashi estimated that a treatment could reach patients in about five years at the earliest. Large clinical trials would first need funding, probably from a pharmaceutical company, she told KUOW.
This article is for information only and does not replace advice from a qualified health professional.
Header image: Trust "Tru" Katsande on Unsplash