# Extension to Study on Efficacy and Safety of Linzagolix for the Treatment of Endometriosis-associated Pain (EDELWEISS 6)

> **NCT04335591** · PHASE3 · COMPLETED · sponsor: **Kissei Pharmaceutical Co., Ltd.** · enrollment: 356 (actual)

## Conditions studied

- Endometriosis

## Interventions

- **DRUG:** 75 mg linzagolix tablet
- **DRUG:** 200 mg linzagolix tablet
- **DRUG:** Placebo tablet to match 75 mg linzagolix tablet
- **DRUG:** Placebo tablet to match 200 mg linzagolix tablet
- **DRUG:** Add-back capsule (E2 1 mg / NETA 0.5 mg)
- **DRUG:** Placebo capsule to match Add-back capsule

## Key facts

- **NCT ID:** NCT04335591
- **Lead sponsor:** Kissei Pharmaceutical Co., Ltd.
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE3
- **Study type:** INTERVENTIONAL
- **Status:** COMPLETED
- **Start date:** 2020-03-05
- **Primary completion:** 2022-09-15
- **Final completion:** 2022-12-15
- **Target enrollment:** 356 (ACTUAL)
- **Last updated:** 2025-04-02


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT04335591

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT04335591, "Extension to Study on Efficacy and Safety of Linzagolix for the Treatment of Endometriosis-associated Pain (EDELWEISS 6)". Retrieved via AI Analytics 2026-06-08 from https://api.ai-analytics.org/clinical/NCT04335591. Licensed CC0.

---

*[Clinical trials dataset](/datasets/clinical-trials) · CC0 1.0*