A medicine normally used to get rid of gut parasites may offer new hope for people living with endometriosis, a painful long-term condition that affects around one in 10 women.
Scientists have reworked the drug so that it targets the cells behind the problem, and it has shown promising results in mice. It’s early days, and nothing has yet been tested in people. Here is what the study found, why the work matters and what you should do if you think you could have the condition.
What is endometriosis?
Endometriosis happens when cells similar to the ones that line the womb start growing in other parts of the body. They can turn up on the ovaries, the bowel, the bladder and elsewhere. Around one in 10 women of reproductive age is thought to have it, which adds up to roughly 190 million people around the world.
These patches of tissue behave as the womb lining does. They respond to the hormones of the monthly cycle, which means they can swell, bleed and break down. Because the blood has nowhere to go, the result is inflammation, pain and a build-up of scar tissue in the affected areas.
What makes it so hard to live with
The condition can cause constant pain in the lower tummy, along with heavy periods, pain during or after sex and deep tiredness. For some people, the pain is so severe that it stops them from working, studying, or seeing friends. It can also make it harder to get pregnant and can weigh on mood and mental health.
At the moment, there is no cure. Treatment is about easing the symptoms, and options range from everyday painkillers and hormonal contraception to surgery that removes the extra tissue. Many people find that these help only partly, which is why researchers are looking for something better.
The unlikely drug that could help
The medicine in this study is called niclosamide, and doctors have used it for years to treat tapeworms and other parasites in the gut. It works by blocking the parasites from taking in glucose, a sugar that is their main source of energy. Without it, they can’t survive.
Earlier research had already hinted that the drug could help with endometriosis because it seems able to calm inflammation and slow the growth of the unwanted tissue. Using an existing medicine in a new way is a popular idea in science, since much of the safety work has already been done. The trouble was that the original drug had some serious drawbacks.
The problems with the original medicine
For a start, it didn’t dissolve well in water, which makes it hard to get into the bloodstream in a useful amount. It also didn’t last long in the body, so its effect faded fast. And it didn’t home in on the places where it was needed most, so much of the dose was wasted.
Those flaws meant that the drug, as it stands, wasn’t a good candidate for treating a long-term condition. The researchers therefore decided to redesign it, in the hope of keeping the benefits while fixing the problems.
How the new version works
The team attached the drug to a large, tree-shaped molecule that helps it dissolve in the blood. They then added other ingredients so that it would target only the faulty immune cells found in endometriosis tissue. As one of the scientists explained, the medicine is attached in such a way that nothing happens while it travels around the body, and it only springs into action once it gets inside the diseased cells.
Once it’s there, it’s released slowly over about two weeks. That steady release is important because it means that a single dose could keep working for a long time. It also means that healthy parts of the body are less likely to be affected.
What happened in the mice
So far, the treatment has been tested only in mice that were bred to develop growths similar to those seen in endometriosis. In these animals, a single injection greatly reduced signs of pain and slowed the growth of new patches of tissue. In some cases, the growths stopped altogether.
That is encouraging, but results in animals don’t always carry over to people. A mouse’s body works differently from ours, and the condition in humans is more complicated. The findings are best seen as a promising first step.
It’s still early days, so more time and research is needed.
An independent researcher who wasn’t involved in the work said there is a lot of promise in finding new uses for medicines that have already been through clinical trials. The next steps are to repeat the study in larger groups of animals and, if the results hold up, to start a first small trial in humans. That kind of trial is mainly designed to check whether a treatment is safe.
Realistically, it could be many years before anything like this reaches patients, and there is no guarantee that it will. Anyone with endometriosis should carry on with the treatment their doctor has advised and not look for this drug.
There are signs to look out for.
It can take a long time to get a diagnosis, sometimes up to eight years, which means a delay in treatment and a risk that symptoms get worse. The NHS lists several signs. They include period pain so bad that it stops you from doing normal things, heavy periods where you need to change your pad or tampon every hour or two, and pain when you go to the toilet.
Other signs, which can occur at any time in your cycle, include pain in the lower tummy and back, pain during or after sex and extreme tiredness. Some people have trouble getting pregnant or feel low or anxious, and in rare cases there can be pain or bleeding elsewhere, such as in the chest. See your GP if you think you might have endometriosis, if your symptoms are affecting your daily life or if treatment isn’t helping.
