2025-524995-53-00RecruitingPhase 4
ENDO-REAL: Endometriosis and Reproductive Enhancement with Letrozole
Reproductive outcomes with letrozole co-treatment during ovarian stimulation in women with endometriosis undergoing IVF/ICSI: a randomised, multicentre, parallel group pragmatic trial
Source: EU CTIS (euclinicaltrials.eu) · Last updated 25 Aug 2026
Brief summary (registry, in English)
The primary objective of this study is to determine whether letrozole co-administration during ovarian stimulation for IVF/ICSI can improve the occurrence of a live birth following embryo transfer(s) in patients diagnosed with endometriosis +/- adenomyosis. Primary outcome will focus on cumulative live birth per stimulation cycle, including fresh and frozen embryo transfers resulting from the same oocyte aspiration and transferred within 1 year (52 weeks) of randomization. Live birth following fresh embryo transfer and number of ETs needed for successful pregnancy will also be evaluated as an important outcome.
- Status (registry)
- Recruiting
- Phase (registry)
- Phase 4
- Study type
- Interventional
- Enrollment
- 854 (estimated)
- First submitted
- 16 Mar 2026
- Start date
- 29 Sept 2026
- Lead sponsor
- UZ Brussel
- Diseases
- Endometriosis
- EU CT number
- 2025-524995-53-00
What you commit to
- Study type: Interventional · Phase 4
- Planned participants: 854
- 11 sites in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of EU CTIS (euclinicaltrials.eu). It describes the study design.
Who cannot take part
Copied verbatim from EU CTIS (euclinicaltrials.eu) and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- Severe OHSS in previous treatment cycle or patients planned in forehand for a freeze-all strategy
Other
- Anti-müllerian hormone (AMH) < 0.5 ng/mL (dosage in the 1 year preceding randomization)
- Abnormal uterine cavity (known mullerian duct anomalies, intra-uterine adhesions or other untreated intra-uterine pathology)
- Untreated tubal factor (hydrosalpinx)
- Any untreated endocrine abnormality
- Surgically obtained sperm
- Ovarian stimulation for pre-implantation genetic testing (PGT-A/M)
Who the study is looking for
- Sub/infertile women with a diagnosis of endometriosis (all types/ stages) either by TVUS/ MRI or surgically and an indication for treatment with IVF/ICSI (based on existing guidelines) are eligible for the study.
- Planned fresh ET following oocyte retrieval
- Patient with and without concomitant adenomyosis will be included
- The patient must have undergone not more than three consecutive unsuccessful IVF/ICSI cycles since the last ongoing pregnancy (whether fresh and/or several frozen ET resulted from these attempts). Each patient may only participate once.
- Age ≥ 18 years and < 40 years
- Body mass Index (BMI) < 35kg/m
- Participant should be capable of giving informed consent
Age in the registry: 18 years to 64 years · Sex: Female · Does not accept healthy volunteers
Sites (11)
Sites in registry order. Save your city in your profile to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| Hopital Erasme | Anderlecht | Belgium | Recruiting |
| Ziekenhuis Aan De Stroom | Antwerp | Belgium | Recruiting |
| AZ ST-JAN Brugge A.V. | Brugge | Belgium | Recruiting |
| Universitair Ziekenhuis Antwerpen | Edegem | Belgium | Recruiting |
| Ziekenhuis Oost-Limburg | Genk | Belgium | Recruiting |
| Universitair Ziekenhuis Gent | Gent | Belgium | Recruiting |
| UZ Brussel | Jette | Belgium | Recruiting |
| UZ Leuven | Leuven | Belgium | Recruiting |
| Centre Hospitalier Regional de la Citadelle | Liège | Belgium | Recruiting |
| CHC MontLégia | Liège | Belgium | Recruiting |
| Cliniques Universitaires Saint-Luc | Sint-Lambrechts-Woluwe | Belgium | Recruiting |
This page is information, not medical advice. Discuss any trial with your doctor.