Phase 2
N=60
Assessment and Prevention of Pain During Ovarian Stimulation in Patients With Endometriosis
Endometriosis · Ovarian Hyperstimulation
Bottom Line
View on ClinicalTrials.gov: NCT04002141 ↗Enrolled (actual)
60
Serious AEs
1.7%
Results posted
Jan 2026
Primary outcome: Primary: Average Delta in Endometriosis Pain Score Pre and Post Stimulation With and Without Use Of Letrozole — -2.5; -2.7 Change in score on a scale
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 2
- Interventions
- Placebo oral tablet (Drug); Letrozole (Drug)
- Age
- Adult · 18+ yrs
- Sex
- Female
- Sponsor
- University of California, San Francisco
- Primary completion
- Oct 2023
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Average Delta in Endometriosis Pain Score Pre and Post Stimulation With and Without Use Of Letrozole |
-2.5; -2.7 | — |
| SECONDARY Average Delta in Endometriosis Pain Score Pre and Post Stimulation of Patients Receiving Placebo Compared to No Endometriosis |
-2.7; -0.6 | — |
| SECONDARY Comparative Trends in Endometriosis Pain Score Pre and Post Stimulation of Patients With Endometriosis Receiving Either Placebo or Letrozole and Patients Without Endometriosis |
-0.7; -1.0; -0.6 | — |
| SECONDARY Does Letrozole Impact Egg Quantity in Endometriosis Patients |
0.84; 0.88; 0.73 | — |
| SECONDARY Follicular Fluid |
— | — |
| SECONDARY Pregnancy Outcomes |
— | — |
| SECONDARY Egg Maturity |
— | — |
| SECONDARY Embryo Grade |
2.9; 2.9; 3.3 | — |
Summary
Randomized double blinded placebo-controlled trial to evaluate the impact of ovarian hyperstimulation on endometriosis-related symptoms and to evaluate the impact of letrozole use during ovarian hyperstimulation with respect to endometriosis-related symptoms, embryo/egg quality and quantity, and pregnancy rates.
Eligibility Criteria
Inclusion Criteria
- Age 18-42 years
- Planning to undergo controlled ovarian hyperstimulation
- Prior diagnosis of endometriosis by one of the following: (1) surgical diagnosis (2) endometrioma on pelvic ultrasound
- Planning to freeze all retrieved oocytes/embryos prior to transfer
Exclusion Criteria
- Hypersensitivity to letrozole
- Any significant concurrent disease, illness, or psychiatric disorder that would compromise patient safety or compliance, interfere with consent, study participation, follow-up, or interpretation of study results
Data sourced from ClinicalTrials.gov (NCT04002141). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.