RecruitingPhase IInterventional

Investigating the use of obafistat on metabolic health in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) affects roughly one in ten women. It is linked to higher levels of male hormones, irregular periods, and a greater risk of health concerns like diabetes and heart problems. Body fat plays a key role because an enzyme inside it turns hormones into active male hormones. Researchers at Imperial College London are testing an experimental tablet called obafistat. Obafistat is designed to block this enzyme and reduce active male hormones in the body. In this early-stage trial, doctors want to see how safe the drug is, how the body handles it, and whether it helps metabolic health. To take part, women must be aged 18 to 42, have PCOS, and have a higher body mass index (BMI). Because the drug could harm an unborn baby, participants must be willing to have a contraceptive coil fitted before taking the study medication.

At a glance

Status

Recruiting

Phase

Phase I

Sponsor

Imperial College London

Enrolment target

Start

15 Mar 2026

Estimated completion

31 May 2028

Polycystic ovary syndrome

What is this study about?

Polycystic ovary syndrome (PCOS), sometimes called polyendocrine metabolic ovarian syndrome (PMOS), is a common condition affecting about one in ten women. Women with PCOS often have higher levels of 'male' hormones (androgens) and struggle to process sugar properly. Over time, this raises the risk of long-term health problems such as type 2 diabetes, high blood pressure, and heart disease.

Recent science shows that body fat is not just storage; it actively produces and activates hormones. In women with PCOS, a specific natural protein called AKR1C3 is found in higher amounts inside fat tissue. This protein switches male hormones into their strongest, most active form, which can make metabolic problems worse.

This trial is testing a new drug called obafistat. Obafistat works by blocking the AKR1C3 protein. Researchers hope this will reduce the amount of active male hormones in both the blood and fat tissue. Because obafistat is in an early stage of development (Phase I), this study is designed to check its safety, understand how the body breaks it down, and see if it brings measurable health benefits.

By taking part, volunteers help doctors discover whether targeting hormone production inside fat tissue could become an effective new way to protect the long-term health of women living with PCOS.

Key takeaways

Phase I study testing a new daily tablet called obafistat for polycystic ovary syndrome (PCOS).
Aims to improve metabolic health by blocking hormone activation in body fat.
Open to women aged 18 to 42 with PCOS and a higher body mass index (BMI).
Requires having a contraceptive coil fitted at least 8 weeks before starting the 8-week treatment.
Takes place at Imperial College London with close medical and liver safety monitoring.

Who may be eligible?

This study is looking for women aged 18 to 42 who have a confirmed diagnosis of PCOS. To meet the criteria, you should have at least two classic signs of PCOS: irregular or absent periods, signs of higher male hormones (such as excess facial or body hair, acne, or high hormone levels on blood tests), or polycystic ovaries seen on an ultrasound scan. Volunteers must also have a body mass index (BMI) in the obesity range (30 or higher, or 27.5 or higher for women of Asian, Chinese, Middle Eastern, Black African, or African-Caribbean backgrounds).

Safety is a top priority. Because blocking male hormones could affect the development of an unborn baby (especially a boy), you must be willing to have a contraceptive coil (the Jaydess IUS) fitted at least 8 weeks before starting the study medicine. You must also agree not to try for a baby during the study and for 6 months after it ends.

You cannot join the trial if you are pregnant, breastfeeding, or have confirmed type 1 or type 2 diabetes. People with other conditions that affect hormones, such as thyroid problems or adrenal gland disorders, are also unable to take part.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you a woman aged between 18 and 42?
Do you have a diagnosis of PCOS with irregular periods or high male hormone levels?
Is your BMI 30 or higher (or 27.5 or higher if you are of Asian, Middle Eastern, or Black heritage)?
Are you willing to have an IUS coil fitted for reliable contraception?
Are you free from diagnosed diabetes and other thyroid or adrenal conditions?
Are you able to travel to London for hospital visits and tests?

Answer every question to see your result.

What does participation involve?

If you are eligible and agree to take part, you will first have a small contraceptive coil (Jaydess) fitted at least 8 weeks before you take any study medication. Once ready, you will be randomly placed into one of two groups: one group takes obafistat once a day for 8 weeks, while the other takes a dummy pill (placebo). Neither you nor the study team can choose which group you are in.

During the 8-week treatment window, you will attend hospital visits at Imperial College London, including some day visits and overnight stays. The team will carry out health checks, take blood samples using a small plastic tube (cannula), and collect saliva and urine samples. They will also take a small fat sample (a biopsy) from your tummy area using a local numbing injection.

Your liver health will be watched very closely with regular blood tests throughout the trial and for 4 weeks after your last dose. The study is scheduled to run between March 2026 and December 2028.

Potential risks and benefits

There is no guarantee that taking part will improve your health, but your results could help doctors find better treatments for PCOS in the future. You will also receive detailed health and hormone check-ups. The main risks involve potential drug side effects. An earlier, different medicine that blocked the same protein caused liver stress, so doctors will monitor your liver closely with regular blood tests to ensure your safety. Taking blood and placing a cannula can cause mild bruising or discomfort. The fat biopsy may cause slight soreness and a small temporary mark, but numbing cream or injections are used to reduce pain. Having a coil fitted can also cause temporary cramping. Taking part is completely your choice, and you can change your mind and leave the study at any time without your regular NHS care being affected.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

NIHR Imperial Clinical Research Facility, Imperial College Healthcare NHS Trust
Unverified
London, England

Common questions

What is obafistat?

Obafistat is an experimental medicine taken as a daily tablet. It is designed to block a specific protein in fat tissue that turns male hormones into their active form.

Will I definitely receive the active medicine?

No. This is a randomised trial, meaning a computer will decide whether you receive obafistat or a placebo (a dummy pill with no active medicine).

Why must I have a contraceptive coil fitted to take part?

Because obafistat lowers male hormones, it could theoretically harm the development of an unborn baby, particularly a male baby. A coil provides very reliable protection against pregnancy during the trial.

Does the fat biopsy hurt?

The area is numbed with a local anaesthetic first so you should not feel sharp pain. You may feel some mild pressure or bruising afterwards, and any small mark usually fades within a few weeks.

Will taking part cure my PCOS?

No. This is an early research study to test drug safety and how it works in the body. It is not designed to be a permanent cure for PCOS.

How to find out more

Aaron Clarke

Akropat@imperial.ac.uk - Official trial record

Always speak to your GP or specialist before deciding to take part in a study.