LETROZOLE for Endometriosis | Adenomyosis | Infertility

Inclusion criteria

• {"criterion_text":"- 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.\n- Planned fresh ET following oocyte retrieval\n- Patient with and without concomitant adenomyosis will be included\n- 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.\n- Age ≥ 18 years and < 40 years\n- Body mass Index (BMI) < 35kg/m\n- Participant should be capable of giving informed consent"}

Exclusion criteria

• {"criterion_text":"- Anti-müllerian hormone (AMH) < 0.5 ng/mL (dosage in the 1 year preceding randomization)\n- Abnormal uterine cavity (known mullerian duct anomalies, intra-uterine adhesions or other untreated intra-uterine pathology)\n- Untreated tubal factor (hydrosalpinx)\n- Any untreated endocrine abnormality\n- Surgically obtained sperm\n- Ovarian stimulation for pre-implantation genetic testing (PGT-A/M)\n- Severe OHSS in previous treatment cycle or patients planned in forehand for a freeze-all strategy"}

Primary endpoints

• {"endpoint_text":"- The primary endpoint is cumulative live birth per stimulation (or IVF/ICSI) cycle, including fresh ET and frozen ETs resulting from the same oocyte aspiration and transferred within 1 year of randomization.","definition_or_measurement_approach":"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."}

Secondary endpoints

• {"endpoint_text":"- LBR per fresh ET cycle (excluding freeze-all), defined as live birth at ≥ 24 weeks of gestation.\n- Number of ETs needed for successful pregnancy\n- Miscarriage rate (defined as pregnancy loss prior to viability scan and including those confirmed on ultrasound scan up to ≤ 23 weeks 6 days gestation) for fresh and frozen ETs.\n- Implantation rate (positive serum βhCG 10-15 days after transfer) for fresh and frozen ETs.\n- Clinical pregnancy rate (at least one gestational sac 4-6 weeks after transfer) for fresh and frozen ETs.\n- Rate of ectopic pregnancy or pregnancy of unknown location for fresh and frozen ETs.\n- For women achieving a pregnancy > 24 weeks: •\tPregnancy related complications: pre-eclampsia and pregnancy-induced hypertension, preterm birth, intrauterine growth restriction, caesarean delivery and obstetric hemorrhage. •\tExtreme preterm birth (24-28 weeks of gestation) •\tStill birth and termination of pregnancy •\tGestational age at delivery, Birthweight •\tNeonatal admission and mortality •\tMajor congenital abnormalities\n- Pain score: NRS 1-10 one to four hours after OPU\n- Patient QOL measured at the day of fresh embryo transfer (OPU +5) and compared to baseline (FertiQOL)","definition_or_measurement_approach":"Definitions provided in endpoints: LBR defined as live birth ≥24 weeks; miscarriage defined as pregnancy loss prior to viability scan up to ≤23 weeks 6 days; implantation rate defined by positive serum βhCG 10-15 days after transfer; clinical pregnancy defined as at least one gestational sac 4-6 weeks after transfer; pain scored by NRS 1-10 one to four hours after OPU; QOL measured using FertiQOL at OPU+5 compared to baseline."}

Belgium

Earliest CTIS Part Ii Submission Date

28-04-2026

Latest Decision Or Authorization Date

13-05-2026

Processing Time Days

15

Number Of Sites

11

Number Of Participants

854

Primary sponsor

Full Name

UZ Brussel

Organisation Type

Hospital/Clinic/Other health care facility

Country Of Registered Address

Belgium