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Letrozole for Frozen Embryo Transfer (FET) in Patients With Polycystic Ovary Syndrome (PCOS) (LEFT)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT04002635
Recruitment Status : Withdrawn (Practical issues)
First Posted : June 28, 2019
Last Update Posted : January 8, 2021
University Hospital, Ghent
Information provided by (Responsible Party):
Liese Boudry, CRG UZ Brussel

Brief Summary:
To offer patients with oligomenorrhoea or amenorrhoea an alternative to frozen embryo transfer in an artificial cycle, endometrial preparation using letrozole may be a valuable option. Letrozole, a potent, reversible nonsteroidal aromatase inhibitor with relatively short half-life, can successfully induce ovulation without any adverse anti-estrogenic effects and thus without affecting the endometrium. The use of letrozole typically results in monofollicular growth and this reduces the effect of supraphysiological levels of estrogen on the endometrium and embryo. The purpose of this study is to compare a frozen-thawed embryo transfer in an artificial cycle with a letrozole-induced ovulatory cycle, specifically in PCOS patients. The primary outcome is early pregnancy loss.

Condition or disease Intervention/treatment Phase
Infertility, Female Polycystic Ovary Syndrome IVF Ovulation Disorder Drug: Letrozole Drug: estradiol valerate Phase 4

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 0 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Endometrial Preparation Using Letrozole Compared to Artificial Cycle for Frozen Embryo Transfer in PCOS Patients
Estimated Study Start Date : December 1, 2020
Estimated Primary Completion Date : April 1, 2021
Estimated Study Completion Date : April 1, 2022

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Active Comparator: Hormonal Replacement Therapy
Artificial preparation of the endometrium using estradiol valerate 2mg 3x/day, and vaginal micronized progesterone 2x 400mg/day.
Drug: estradiol valerate
hormonal replacement therapy
Other Name: progesterone

Experimental: Letrozole
Using letrozole for ovulation induction before planning the frozen embryo transfer
Drug: Letrozole
Letrozole ovulation induction

Primary Outcome Measures :
  1. early pregnancy loss [ Time Frame: 12 weeks after frozen embryo transfer ]

Secondary Outcome Measures :
  1. cancellation rate [ Time Frame: 2 months ]
  2. number of visits to the clinic [ Time Frame: 2 months ]
  3. endometrial thickness on the day of planning of FET [ Time Frame: 1 day ]
  4. implantation rate [ Time Frame: 1 day ]
  5. biochemical and clinical pregnancy rate [ Time Frame: 12 weeks ]
  6. live birth rate [ Time Frame: 1 year ]
  7. neonatal birth weight [ Time Frame: 1 year ]
  8. term of delivery [ Time Frame: 1 year ]
  9. hypertensive disorders of pregnancy [ Time Frame: 1 year ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Age more than or equal to 18 and less than or equal to 40
  • BMI more than or equal to 18 and less than or equal to 35
  • Diagnosis of PCOS according to Rotterdam criteria
  • Normal gynaecological ultrasound < 6 months before inclusion
  • Signed informed consent form
  • Day 5 or 6 frozen-thawed embryo transfer, blastocyst stage

Exclusion Criteria:

  • Recurrent implantation failure
  • Recurrent miscarriage
  • Presence of adenomyosis
  • Untreated intrauterine pathology
  • rAFS (revised American Fertility Society) Grade III or IV endometriosis
  • Hydrosalpinx
  • In vitro maturation (IVM)
  • Untreated autoimmune disorders
  • (History of) malignancy
  • Allergy or reaction to the use of progynova, utrogestan and/or letrozole in the past
  • Pre-implantation genetic testing (PGT)
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Responsible Party: Liese Boudry, Medical doctor, CRG UZ Brussel Identifier: NCT04002635    
Other Study ID Numbers: 2019LEFT001
First Posted: June 28, 2019    Key Record Dates
Last Update Posted: January 8, 2021
Last Verified: January 2021
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description: Sharing with other study site, UZ Gent
Supporting Materials: Study Protocol
Statistical Analysis Plan (SAP)
Informed Consent Form (ICF)
Clinical Study Report (CSR)
Analytic Code

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Keywords provided by Liese Boudry, CRG UZ Brussel:
frozen embryo transfer
Additional relevant MeSH terms:
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Polycystic Ovary Syndrome
Infertility, Female
Pathologic Processes
Ovarian Cysts
Ovarian Diseases
Adnexal Diseases
Gonadal Disorders
Endocrine System Diseases
Estradiol 3-benzoate
Estradiol 17 beta-cypionate
Polyestradiol phosphate
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs
Contraceptive Agents
Reproductive Control Agents
Contraceptive Agents, Female
Antineoplastic Agents
Aromatase Inhibitors
Steroid Synthesis Inhibitors
Enzyme Inhibitors