For women diagnosed with endometriosis it is often a long sentence of chronic pain and cramping that impacts their daily life. It is a condition that is both difficult to diagnose and treat, with many women needing either surgery or regular medication.

A medicine called Ryeqo has just been approved for marketing specifically for endometriosis, although it was already available in Australia to treat a different condition.

Women who want the drug will need to consult their local doctor and, as it is not yet on the Pharmaceutical Benefits Scheme, they will need to pay the full cost of the script.

What does Ryeqo do?

Endometriosis affects 14% of women of reproductive age. While we don’t have a full understanding of the cause, the evidence suggests it’s due to body tissue that is similar to the lining of the uterus (called the endometrium) growing outside the uterus. This causes pain and inflammation, which reduces quality of life and can also affect fertility.

Ryeqo is a tablet containing three different active ingredients: relugolix, estradiol and norethisterone.

Relugolix is a drug that blocks a particular peptide from releasing other hormones. It is also used in the treatment of prostate cancer. Estradiol is a naturally occurring oestrogen hormone in women that helps regulate the menstrual cycle and is used in menopausal hormone therapy. Norethisterone is a synthetic hormone commonly used in birth control medications and to delay menstruation and help with heavy menstrual bleeding.

All three components work together to regulate the levels of oestrogen and progesterone in the body that contribute to endometriosis, alleviating its symptoms.

Relugolix reduces the overall levels of oestrogen and progesterone in the body. The estradiol compensates for the loss of oestrogen because low oestrogen levels can cause hot flushes (also called hot flashes) and bone density loss. And norethisterone blocks the effects of estradiol on the uterus (where too much tissue growth is unwanted).

Is it really new?

The maker of Ryeqo claims it is the first new drug for endometriosis in Australia in 13 years.

But individually, all three active ingredients in Ryeqo have been in use since 2019 or earlier.

Ryeqo has been available in Australia since 2022, but until now was not specifically indicated for endometriosis. It was originally approved for the treatment of uterine fibroids, which share some common symptoms with endometriosis and have related causes.

In addition to Ryeqo, current medical guidance lists other drugs that are suitable for endometriosis and some reformulations of these have also only been recently approved.

The oral medicine Dienogest was approved in 2021, and there have been a number of injectable drugs for endometriosis recently approved, such as Sayana Press which was approved in a smaller dose form for self-injection in 2023.

How to take it and what not to do

Ryeqo is a once-a-day tablet. You can take it with, or without food, but it should be taken about the same time each day.

It is recommended you start taking Ryeqo within the first five days after the start of your next period. If you start at another time during your period, you may experience initial irregular or heavier bleeding.

Because it contains both synthetic and natural hormones, you can’t use the contraceptive pill and Ryeqo together. However, because Ryeqo does contain norethisterone it can be used as your contraception, although it will take at least one month of use to be effective. So, if you are on Ryeqo, you should use a non-hormonal contraceptive – such as condoms – for a month when starting the medicine.

Ryeqo may be incompatible with other medicines. It might not be suitable for you if you take medicines for epilepsy, HIV and AIDS, hepatitis C, fungal or bacterial infections, high blood pressure, irregular heartbeat, angina (chest pain), or organ rejection. You should also not take Ryeqo if you have a liver tumour or liver disease.

The possible side effects of Ryeqo are similar to those of oral contraceptives. Blood clots are a risk with any medicine that contains an oestrogen or a progestogen, which Ryeqo does. Other potential side effects include bone loss, a reduction in menstrual blood loss or loss of your period.

It’s costly for now

Ryeqo can now be prescribed in Australia, so you should discuss whether Ryeqo is right for you with the doctor you usually consult for your endometriosis.

While the maker has made a submission to the Pharmaceutical Benefits Advisory Committee, it is not yet subsidised by the Australian government. This means that rather than paying the normal PBS price of up to A$31.60, it has been reported it may cost as much as $135 for a one-month supply. The committee will make a decision on whether to subsidise Ryeqo at its meeting next month.

Correction: this article has been updated to clarify the recent approval of specific formulations of drugs for endometriosis.

Nial Wheate, Associate Professor of the School of Pharmacy, University of Sydney and Jasmine Lee, Pharmacist and PhD Candidate, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.