Extended High Dose Letrozole Regimen Versus Short Low Dose Letrozole Regimen as an Adjuvant to GnRH Antagonist Protocol in the Management of Poor Responders Undergoing IVF-ET

Study Overview
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Brief Summary
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The aim of this randomized controlled trial is to compare the efficacy of extended high dose letrozole regimen (5 mg /day for the first 5 days of cycle and 2.5 mg/day for the subsequent 3 days ) with short low dose letrozole regimen (2,5 mg/day from cycle day 3 to 7 ) as an adjuvant to GnRH antagonist protocol in the management of patients with poor ovarian response undergoing IVF-ET.

Detailed Description
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Poor response to controlled ovarian stimulation (COH) is estimated to occur in 9-24 % of all IVF cycles. Although there is no consensus on the definition of poor response to COH, inability to produce adequate number of mature follicles( ≤ 2-5) or to recruit adequate number of oocytes ( ≤ 3 oocytes ) in response to standard stimulation protocols are the main criteria used for diagnosis of poor responders . Patients with poor response to COH usually have higher cyclical cancelation rate , poor embryo quality and less number of embryos suitable for transfer or cryopreservation . During the past decade gonadotropin releasing hormone antagonists (GnRHant) were widely used in the treatment of patients with poor response to standard gonadotropin releasing hormone agonist (GnRHa) protocols .In contrast to GnRHa, GnRHant is administered at the late follicular phase and therefore don't suppress the early follicular phase endogenous gonadotropins and has no suppressive effect on ovarian function at the stage of follicular recruitment.Several studies comparing GnRHant protocol with the standard GnRHa long protocol revealed a reduction in the duration of stimulation , dose of required gonadotropins , and the costs of IVF cycle with GnRHant as well as equivalent pregnancy rates . In 2001, Mitwally and Casper introduced letrozole ( a third generation non steroidal aromatase inhibitor licensed for treatment of hormonally-responsive breast cancer after surgery ) as new ovulation induction agent in clomiphene citrate resistant patients with polycystic ovary syndrome (PCOS) . Subsequent studies confirmed the effectiveness of letrozole in induction of ovulation in women with PCOS and in superovulation (either alone or in combination with gonadotropins ) . In patients with poor response undergoing IVF, several studies revealed that the combination of letrozole ( 2.5 mg or 5 mg/day for 5 consecutive days in early follicular phase ) with GnRHant protocol improved the ovarian response and reduced the gonadotrophin dose required. On the other hand , Schoolcraft et al reported that letrozole(2.5 mg/day from cycle day 3 to 7)/GnRHant protocol has no advantages over microdose flare GnRHa protocol. The ideal dose and duration of letrozole administration for ovulation and superovulation is still not clear. Several studies comparing two doses of letrozole (2.5 mg or 5 mg) in superovulation suggested that the higher dose might be associated with more follicles developing. In almost all studies to date , letrozole was administered for five consecutive days in early follicular phase . In only one study , letrozole (2.5 mg/day) was administered for ten consecutive days starting on day 1 of menstrual cycle . In that study , prolonged administration of letrozole produced more mature follicles and pregnancies than short letrozole therapy regimen in patients with clomiphene citrate resistant polycystic ovary syndrome . The investigators designed this randomized controlled trial to compare the efficacy of extended high dose letrozole regimen (5 mg /day for the first 5 days of cycle and 2.5 mg/day for the subsequent 3 days ) with conventional short low dose letrozole regimen (2,5 mg/day from cycle day 3 to 7 ) as an adjuvant to GnRHant protocol in the management of patients with poor ovarian response undergoing IVF-ET.

Official Title
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Extended High Dose Letrozole Regimen Versus Short Low Dose Letrozole Regimen as an Adjuvant to GnRH Antagonist Protocol in the Management of Patients With Poor Ovarian Response Undergoing IVF-ET, a Randomized Controlled Trial

Conditions
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Infertility

Intervention / Treatment
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* Drug: Extended high dose letrozole regimen /GnRH antagonist protocol
* Drug: Short low dose letrozole regimen /GnRH antagonist protocol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who produced less than three mature follicles in response to standard GnRH agonist long protocol in their first IVF cycle Exclusion Criteria: Age > 42 years FSH> 12 IU/L Irregular menstrual cycles Unilateral ovary Polycystic ovary syndrome Endometriosis Male factor of infertility requiring ICSI History of recurrent miscarriage Endocrinologic disorders Systemic disease contraindicating pregnancy

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 42 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Extended high dose letrozole regimen /GnRH antagonist<br> | Drug: Extended high dose letrozole regimen /GnRH antagonist protocol<br>* Letrozole (Femara; Novertis pharma AG, Basle, Switzerland) is administered starting on cycle day one for 8 consecutive days . The dose of letrozole is 5mg /day during the first 5 days of cycle and 2.5 mg/day during the subsequent 3 days . Highly purified urinary FSH (HP-uFSH) (Fostimon, IBSA) 300 IU/day is started on cycle day 5 and is continued until and including the day of HCG administration. Starting from cycle day 8 , the dose of HP-uFSH is adjusted individually according to ovarian response which is monitored using transvaginal ultrasound and serum estradiol. GnRH antagonist (cetrorelix acetate)(Cetrotide®) 0.25 mg S.C once daily is started when the leading follicle is 14 mm in mean diameter and is continued until and including the day of HCG administration .<br>* Other names: Extended letrozole/GnRHant;|
| Active Comparator: Short low dose letrozole regimen /GnRH antagonist<br> | Drug: Short low dose letrozole regimen /GnRH antagonist protocol<br>* Letrozole (Femara; Novertis pharma AG, Basle, Switzerland)2.5 mg /daily is administered for 5 consecutive days starting on cycle day 3. Highly purified urinary FSH (HP-uFSH) (Fostimon, IBSA) 300 IU/day is started on cycle day 3 and is continued until and including the day of HCG administration. Starting from cycle day 8 , the dose of HP-uFSH is adjusted individually according to ovarian response which is monitored using transvaginal ultrasound and serum estradiol. GnRH antagonist (cetrorelix acetate)(Cetrotide®) 0.25 mg S.C once daily is started when the leading follicle is 14 mm in mean diameter and is continued until and including the day of HCG administration .<br>* Other names: Short Letrozole/GnRHant;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical pregnancy rate per started cycle | Presence of intrauterine gestational sac detected by transvaginal ultrasound | 5 weeks after embryo transfer | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ongoing Pregnancy Rate per started cycle | Pregnancies continued beyond 20 weeks gestation | 18 weeks after embryo transfer | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Letrozole ,IVF, poor responders , GnRH antagonist