In short
Linzagolix is a gonadotropin-releasing hormone (GnRH) antagonist, a type of hormone-modulating medicine. It is authorised in the UK as Yselty for treating moderate to severe symptoms of uterine fibroids and symptoms of endometriosis. It is also being studied in a Phase 2 trial to see whether it can reduce breast density in women at high risk of breast cancer.
Key points
- Linzagolix is a GnRH antagonist used to treat uterine fibroids and endometriosis.
- It is authorised in the UK as Yselty tablets, available in 100 mg and 200 mg strengths.
- A Phase 2 trial is testing linzagolix for reducing breast density in women at high risk of breast cancer.
- The breast density trial plans to enrol 150 participants and compares linzagolix with bilastine and a control group.
- The trial's main measure is the percentage change in mammographic breast density from baseline to 12 months.
- The trial status is Authorised, meaning it is approved to begin recruitment.
What is linzagolix?
Linzagolix is a gonadotropin-releasing hormone (GnRH) antagonist, a medicine that reduces the production of sex hormones by the ovaries. It is sold under the brand name Yselty and is available as film-coated tablets in 100 mg and 200 mg strengths. In the UK, linzagolix is authorised for treating moderate to severe symptoms of uterine fibroids, in line with NICE technology appraisal TA996, and for treating symptoms of endometriosis in adults of reproductive age who have had medical or surgical treatment for their endometriosis, in line with NICE TA1067.
How does linzagolix work?
Linzagolix blocks the action of gonadotropin-releasing hormone (GnRH) at its receptor in the pituitary gland. This reduces the release of luteinising hormone (LH) and follicle-stimulating hormone (FSH), which in turn lowers oestrogen and progesterone levels in the body. Because conditions such as uterine fibroids and endometriosis are sensitive to these hormones, lowering their levels can reduce symptoms like heavy menstrual bleeding and pelvic pain.
Which conditions is linzagolix used or studied for?
- Uterine fibroids — non-cancerous growths in the womb that can cause heavy periods, pain and pressure. Linzagolix is authorised for moderate to severe symptoms of this condition.
- Endometriosis — a condition where tissue similar to the womb lining grows outside the womb, causing pain and sometimes fertility problems. Linzagolix is authorised for treating symptoms in adults of reproductive age who have already had treatment for endometriosis.
- Increased risk of breast cancer — linzagolix is being studied in a Phase 2 trial to see whether it can reduce breast density, a risk factor for breast cancer, in premenopausal women at high risk.
How is linzagolix given?
Linzagolix is given by mouth as a film-coated tablet. The authorised product Yselty is available in 100 mg and 200 mg tablet strengths. In the breast density trial, linzagolix is being given as 100 mg tablets taken orally.
What do the clinical trials show?
One clinical trial of linzagolix is currently listed in the EU Clinical Trials Information System. This is a Phase 2 interventional trial that plans to enrol 150 participants. The trial status is Authorised, meaning it has been approved and may begin or is beginning recruitment.
Who can take part in the breast density trial?
The trial is for women who have not yet gone through menopause and are at high risk of breast cancer. The study compares three groups: one receiving linzagolix 100 mg tablets, one receiving bilastine 20 mg tablets, and a control group.
What is the trial measuring?
The primary outcome is the relative percentage change in mammographic breast density from baseline to 12 months. This is assessed using the automated LIBRA quantitative mammographic density assessment system, which measures the percentage of dense area in the breast. The aim is to compare the relative change in breast density between the linzagolix, bilastine and control groups over 12 months.
What side effects are known?
The sources provided do not list side effects for linzagolix. The formulary entries describe its authorised uses and tablet strengths but do not give a side-effect profile.