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A Comparison of Letrozole and Clomifene Citrate

The University of Hong Kong (HKU) logo

The University of Hong Kong (HKU)

Status

Unknown

Conditions

Subfertility
Polycystic Ovarian Syndrome

Treatments

Drug: Letrozole
Drug: Clomiphene

Study type

Interventional

Funder types

Other

Identifiers

NCT02647424
HKU-VL-LCC

Details and patient eligibility

About

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies, affecting 5% to 10% of women of reproductive age. Women with PCOS suffer from anovulatory infertility. Following lifestyle modification with weight reduction in obese PCOS women, clomifene citrate (CC) is considered the first line treatment for ovulation induction (OI) in these women. 75-80% of women will ovulate after CC administration. However, there is a discrepancy between the ovulation rate and pregnancy rate, which was reported to be 22% per each ovulating cycles after CC. Other alternatives, including gonadotropin injections and laparoscopic ovarian drilling, carried different disadvantages, such as costly treatment and risks of ovarian hyperstimulation syndrome and multiple pregnancy rate in gonadotrophin therapy and surgical risks and risk of ovarian failure in surgical treatment.

The use of aromatase inhibitor, letrozole (LTZ), in reproductive medicine started in 2001. After this publication, there have been many groups of investigators studying the use of LTZ either in OI or ovarian stimulation in IVF cycles. A large multicentre randomized trial reported a significantly higher ovulation rate and live-birth rate comparing LTZ with CC. In majority of the publications, the multiple pregnancy rate was lower in LTZ group than in CC group. This can be attributed to the higher chance of monofollicular development after LTZ compared with CC. However, there is no information comparing the hormonal profile and follicular development after letrozole and CC.

Mild ovarian stimulation using LTZ or CC in conjunction with intrauterine insemination is commonly offered to ovulatory women with unexplained infertility, minimal endometriosis or mild factor to improve the pregnancy rate. There is again no information comparing the hormonal profile and follicular development after letrozole and CC in ovulatory women.

The aim of this study is to compare the hormonal profile after the use of LTZ and CC in anovulatory PCOS women and ovulatory women with unexplained subfertility. The hypothesis is that the FSH risk after LTZ is shorter than that of CC.

Full description

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies, affecting 5% to 10% of women of reproductive age. Women with PCOS suffer from anovulatory infertility. Following lifestyle modification with weight reduction in obese PCOS women, clomifene citrate (CC) is considered the first line treatment for ovulation induction (OI) in these women. 75-80% of women will ovulate after CC administration. However, there is a discrepancy between the ovulation rate and pregnancy rate, which was reported to be 22% per each ovulating cycles after CC. Other alternatives, including gonadotropin injections and laparoscopic ovarian drilling, carried different disadvantages, such as costly treatment and risks of ovarian hyperstimulation syndrome and multiple pregnancy rate in gonadotrophin therapy and surgical risks and risk of ovarian failure in surgical treatment.

The use of aromatase inhibitor, letrozole (LTZ), in reproductive medicine started in 2001. After this publication, there have been many groups of investigators studying the use of LTZ either in OI or ovarian stimulation in IVF cycles. A large multicentre randomized trial reported a significantly higher ovulation rate and live-birth rate comparing LTZ with CC. In majority of the publications, the multiple pregnancy rate was lower in LTZ group than in CC group. This can be attributed to the higher chance of monofollicular development after LTZ compared with CC. However, there is no information comparing the hormonal profile and follicular development after letrozole and CC.

Mild ovarian stimulation using LTZ or CC in conjunction with intrauterine insemination is commonly offered to ovulatory women with unexplained infertility, minimal endometriosis or mild factor to improve the pregnancy rate. There is again no information comparing the hormonal profile and follicular development after letrozole and CC in ovulatory women.

The aim of this study is to compare the hormonal profile after the use of LTZ and CC in anovulatory PCOS women and ovulatory women with unexplained subfertility. The hypothesis is that the FSH risk after LTZ is shorter than that of CC.

Enrollment

40 estimated patients

Sex

Female

Ages

18 to 39 years old

Volunteers

No Healthy Volunteers

Inclusion criteria

  • Age of women 18-39 years
  • Irregular menstrual cycles with anovulation (cycle >35 days) together with polycystic ovaries on pelvic scanning or laboratory/clinical hyperandrogenism (in PCOS group)
  • Regular cycle of 25-35 days cycle for the ovulatory women group
  • Body mass index </= 30 kg/m2

Exclusion criteria

  • Couples undergoing ART treatment cycles
  • History of ovarian surgery
  • Drug allergy to CC or LTZ
  • History of diabetes mellitus or other severe medical diseases
  • Refusal to join the study

Trial design

Primary purpose

Treatment

Allocation

Non-Randomized

Interventional model

Single Group Assignment

Masking

None (Open label)

40 participants in 2 patient groups

PCOS group
Other group
Description:
PCOS women with anovulation
Treatment:
Drug: Clomiphene
Drug: Letrozole
Ovulatory group
Other group
Description:
Ovulatory group planned for intra-uterine insemination
Treatment:
Drug: Clomiphene
Drug: Letrozole

Trial contacts and locations

1

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Central trial contact

Vivian Lee, MBBS, MRCOG

Data sourced from clinicaltrials.gov

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