RecruitingPhase IInterventional

First in woman safety and ease of use assessment of 400 mg progesterone Callavid in women with luteal phase progesterone insufficiency

This study is for women aged 18 to 45 who have experienced at least one miscarriage and have low progesterone. It's a 'Phase 1' study, meaning we're checking the safety and how easy it is to use a new vaginal progesterone treatment called Callavid. We'll compare it with a treatment already in use, Cyclogest, over three short periods. Participants will use one treatment, then switch to the other, to see how they feel and if there are any side effects. The study aims to help researchers understand if this new treatment could be a good option for future use in helping women carry a pregnancy to term.

At a glance

Status

Recruiting

Phase

Phase I

Sponsor

Calla Lily Clinical Care Ltd

Enrolment target

Start

01 Apr 2026

Estimated completion

30 Aug 2026

Women who have had at least one miscarriage and have luteal phase progesterone insufficiency

What is this study about?

This study, called 'First in Woman', is looking at a new vaginal progesterone treatment called Callavid. Progesterone is a hormone that's very important for getting pregnant and staying pregnant. Some women have what's called 'luteal phase progesterone insufficiency', which means their progesterone levels might not be high enough after ovulation, potentially making it harder to maintain a pregnancy. This study is for women who have experienced miscarriages and have this progesterone issue.

The main goal of this particular study is to check if this new Callavid treatment is safe for women to use and how easy it is. It's a very early stage of research, often called 'Phase 1'. Researchers will compare Callavid to another progesterone treatment called Cyclogest, which is already used. By doing this, they hope to learn more about how Callavid works and whether it could be a helpful new option in the future for women facing fertility challenges.

Understanding how new treatments like Callavid work is a vital step in improving advice and care for women who have had miscarriages. This research helps build our knowledge, potentially leading to better support for maintaining healthy pregnancies down the line.

Key takeaways

This study is testing a new progesterone treatment (Callavid) for safety and ease of use.
It's for women who have had miscarriages and low progesterone levels.
You would use Callavid and an existing treatment (Cyclogest) vaginally.
Participation involves up to six hospital visits, each around six hours.
Potential side effects include discharge, bloating, and breast tenderness.
Your involvement helps improve future care for women with fertility challenges.

Who may be eligible?

This study is looking for women aged between 18 and 45 years old.

You might be able to take part if you have been diagnosed with what's called 'luteal phase insufficiency'. This is when there might not be enough progesterone in the second half of your menstrual cycle. Signs of this can include spotting before your period starts, a short time between when you ovulate and when your period begins, or other symptoms that suggest low progesterone. You must also have experienced at least one miscarriage in the past.

You wouldn't be able to join if you are currently pregnant or breastfeeding, or if you have known allergies to progesterone or similar medications. Also, if you have certain medical conditions where hormone treatments are not recommended (like some types of cancer), or if you can't attend the hospital visits or understand English, this study wouldn't be suitable for you.

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 45?
Have you had at least one miscarriage?
Have you been told you have low progesterone (luteal phase insufficiency)?
Are you able to attend hospital visits in Coventry, UK?
Do you understand English well enough to follow study instructions?
Are you not currently pregnant or breastfeeding?

Answer every question to see your result.

What does participation involve?

If you join this study, you'll be one of two groups decided by chance. For each round, you'll use either the new Callavid treatment or Cyclogest, which is an existing progesterone treatment. Both are vaginal pessaries and are used twice a day for 7 days. In the first round, depending on your group, you'll use either Callavid (for 2 hours) or Cyclogest first, then swap to the other. In the third round, everyone will use Callavid again, but this time for 3 hours.

This means you'll attend the hospital up to six times, each visit lasting about six hours. These visits will involve various assessments. The whole study is expected to run from January to August 2026. The researchers understand that coming to the hospital for these visits can be a commitment, so they will offer some payment for your time and can also help with childcare costs if needed.

Potential risks and benefits

Participating in this study might offer a chance to contribute to medical research, helping future women with similar experiences. However, there are potential risks to consider. Common side effects of progesterone can include vaginal discharge, feeling bloated, tender breasts, and sometimes mood changes. It might also occasionally affect the length of your period. Because Callavid is a new treatment, there's a small chance it might not deliver as much progesterone as the standard treatment, which could lower your chance of getting pregnant during that specific menstrual cycle. The researchers have plans in place to support you if any questions during interviews cause distress. You are always free to leave the study at any time, for any reason, without it affecting your medical care.

Locations (1)

University Hospital Coventry
Approximate
Coventry, England

Common questions

What is progesterone and why is it important?

Progesterone is a natural hormone vital for pregnancy. It helps prepare your womb and supports an early pregnancy.

What is 'luteal phase progesterone insufficiency'?

This means your body might not be making enough progesterone after you ovulate, which can sometimes make it harder to get or stay pregnant.

Will I know which treatment I'm receiving?

Yes, you'll know which treatment you are using during each round of the study.

How long will I be involved in the study?

The study runs from January to August 2026, and your involvement would be for up to six hospital visits, each lasting around six hours.

Can I leave the study if I change my mind?

Yes, you can choose to leave the study at any time, for any reason, and it won't affect your medical care.

How to find out more

Violet Matthews

freedomstudyoffice@uhcw.nhs.uk +44 (0)2476 966197 Official trial record

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