Letrozole vs Danazol for Endometriosis-Related Pain: Randomized Trial

NCT07183787 | Completed Phase 2

• 1 other identifier: SMDC/SMRC/79-18
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

Background: Endometriosis is a chronic gynecological condition defined by the ectopic presence of endometrial glands and stroma outside the uterine cavity, most commonly diagnosed via laparoscopy. While its exact etiology remains uncertain, a positive family history is considered a significant risk factor. Danazol has historically demonstrated efficacy in alleviating endometriosis-related pain, while letrozole, primarily used in neoadjuvant settings, has recently emerged as a promising alternative. This study aimed to compare the mean reduction in pain scores between letrozole and danazol in women with laparoscopically confirmed endometriosis. Objective: To compare the efficacy of letrozole versus danazol in reducing pain scores among women diagnosed with endometriosis. Material \& Methods: Study Design: Randomized control trial Setting: Department of Obstetrics \& Gynaecology, Sharif Medical and Dental Hospital

Conditions

Endometriosis

Outcome Measures

Primary Outcomes (1)

• Change in pelvic pain severity (0-10 Numeric Rating Scale)

  Mean change in pelvic pain scores measured on a 0-10 numeric rating scale; lower scores indicate improvement.

  12 weeks

Secondary Outcomes (1)

• Change in dysmenorrhea severity

  12 weeks

Study Arms (2)

Arm 1: Letrozole

EXPERIMENTAL

Participants in this arm will receive Letrozole 2.5 mg orally once daily for 12 weeks for management of endometriosis-related pelvic pain.

Drug: Letrozole

Arm 2: Danazol

ACTIVE COMPARATOR

Participants in this arm will receive Danazol 200 mg orally twice daily for 12 weeks for management of endometriosis-related pelvic pain.

Drug: danazol

Interventions

Letrozole DRUG

Letrozole 2.5 mg orally once daily for 12 weeks.

Arm 1: Letrozole

danazol DRUG

Danazol 200 mg orally twice daily for 12 weeks.

Arm 2: Danazol

Eligibility Criteria

• Age: 18 Years - 45 Years
• Gender Eligibility Details: Only biologically female participants are eligible, as endometriosis occurs in women.
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Women aged 18-45 years
• Surgically or clinically diagnosed endometriosis
• Moderate to severe pelvic pain (NRS ≥ 4 for at least 3 months)
• Willing to use effective contraception during the study
• Able to provide informed consent

You may not qualify if:

• Pregnant or breastfeeding
• Severe hepatic disease, thromboembolic disorder, or contraindication to study drugs
• Use of hormonal therapy within the last 8 weeks
• Known hypersensitivity to Letrozole or Danazol
• Participation in another clinical trial within the last 3 months

Sponsors & Collaborators

• Sidra Salman: lead

Study Sites (1)

Sharif Medical and Dental College

Lahore, Punjab Province, 54700, Pakistan

Location

Related Publications (6)

• Haqnawaz F, Virk S, Qadir T, Imam S, Rizvi J. Comparison of Letrozole and Clomiphene Citrate Efficacy along with Gonadotrophins in Controlled Ovarian Hyperstimulation for Intrauterine Insemination Cycles. J Reprod Infertil. 2013 Jul;14(3):138-42.

  PMID: 24163798 BACKGROUND

• Rasul SG, Yaqub U, Manzoor M, Mubasshar H. Comparison of Letrozole versus Danazol for the pain management of females presented with endometriosis. Annals of King Edward Medical University. 2017;23(4):514-8.

  BACKGROUND

• Mehmud G, Akhtar T, Sadia S. Endometriosis: frequency and correlation between symptomatology and disease stage. J Coll Physicians Surg Pak. 2007 Apr;17(4):199-202.

  PMID: 17462175 BACKGROUND

• García E, Cruz OP. Regulation of Inflammation Pathways and Inflammasome by Sex Steroid. Reproduction and the Inflammatory Response. 2022:607539061.

  BACKGROUND

• Khashchenko EP, Uvarova EV, Fatkhudinov TK, Chuprynin VD, Asaturova AV, Kulabukhova EA, Vysokikh MY, Allakhverdieva EZ, Alekseeva MN, Adamyan LV, Sukhikh GT. Endometriosis in Adolescents: Diagnostics, Clinical and Laparoscopic Features. J Clin Med. 2023 Feb 20;12(4):1678. doi: 10.3390/jcm12041678.

  PMID: 36836214 BACKGROUND

• Arafah M, Rashid S, Akhtar M. Endometriosis: A Comprehensive Review. Adv Anat Pathol. 2021 Jan;28(1):30-43. doi: 10.1097/PAP.0000000000000288.

  PMID: 33044230 BACKGROUND

MeSH Terms

Conditions

Endometriosis

Interventions

Letrozole; Danazol

Condition Hierarchy (Ancestors)

Genital Diseases, Female; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Genital Diseases

Intervention Hierarchy (Ancestors)

Nitriles; Organic Chemicals; Triazoles; Azoles; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Pregnadienes; Pregnanes; Steroids; Fused-Ring Compounds; Polycyclic Compounds

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: This is an open-label study due to differences in drug formulations. Participants and investigators will know the assigned intervention; outcomes will be measured using validated patient-reported scales to reduce bias."
• Purpose: TREATMENT
• Intervention Model: FACTORIAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: FCPS TRANIEE

Model Details: This is a randomized, parallel-group trial with two treatment arms. Participants will be allocated to receive either Letrozole or Danazol for management of endometriosis-related pain. Each participant will remain in their assigned arm throughout the study period.

Study Record Dates

• First Submitted: September 14, 2025
• First Posted: September 19, 2025
• Study Start: April 10, 2019
• Primary Completion: October 10, 2019
• Study Completion: July 31, 2025
• Last Updated: September 19, 2025

Record last verified: 2019-12

Data Sharing

• IPD Sharing: Will not share

Locations

PA (1)