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EndometriosisPhase 3NCT04335591

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

A Phase 3 study testing 75 mg linzagolix tablet, 200 mg linzagolix tablet and Add-back capsule (E2 1 mg / NETA 0.5 mg) in people with Endometriosis, run by Kissei Pharmaceutical Co., Ltd. at 47 sites in 9 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

The primary objective of this extension study is to assess the maintenance of efficacy of linzagolix administered orally once daily for up to an additional 6 months (for up to 12 months of treatment in total) in women who have already completed 6 months of linzagolix treatment at a dose of 75 mg alone or of 200 mg in… Read more about this study

Who is it for?
Ages 18 to 50 years, women only
Conditions the study is for
Endometriosis
What is being tested?
75 mg linzagolix tablet, 200 mg linzagolix tablet and Add-back capsule (E2 1 mg / NETA 0.5 mg)
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
356 participants
Where
47 sitesin 9 countries
Study dates
5 Mar 2020to 15 Dec 2022
Phase
Phase 3
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 50 years
  • Women only
  • No healthy volunteers
  • Adult

Who may be able to join

  • The subject must have:
  • completed the 6-month treatment in the main study.
  • agree to continue to use only the analgesic rescue medication permitted by the protocol during the Treatment and Follow-up Periods.
  • To continue to comply with the requirements of the study protocol for the duration of the extension study.

Who cannot join

  • The subject will be excluded if she:
  • Is pregnant or breast feeding or is planning a pregnancy within the duration of the of the study (including the Follow-up Period).
  • likely to require treatment during the study with any of the restricted medications
  • has any other clinically significant gynecologic condition identified during the main study on transvaginal ultrasound (TVUS), on endometrial biopsy or at the manual breast examination, which might interfere with the study efficacy and safety objectives.
  • met any of the main study discontinuation criteria

Trial locations and contacts

47 sites in 9 countries.

47 sites in 9 countries

Poland11 sites

  • Prywatna Klinika Ginekologiczno - Położnicza/ ID # 404

    Bialystok, Podlaskie Voivodeship, 15-224

  • Indywidualna Specjalistyczna Praktyka Lekarska Krzysztof Wilk/ ID # 411

    Katowice, 40-301

  • Clinical Medical Research sp. Z o. O/ ID # 406

    Katowice, 40-628

  • Niepubliczny Zaklad Opieki Zrowotnej GynCentrum/ ID # 407

    Katowice, 40-851

  • Kotarski Jan Specjalistyczny Gabinet Ginekologiczno Polozniczy/ ID # 405

    Lublin, 20-064

  • Centrum Medyczne Chodźki Lublin/ ID # 403

    Lublin, 20-093

  • VITA LONGA Sp. z o.o./ ID # 408

    Lublin, 20-093

  • Centrum Ginekologii Endokrynologii i Medycyny Rozrodu "Artemida"/ ID # 409

    Olsztyn, 10-357

  • Wojewodzki Szpital im. Sw. Ojca Pio w Przemyslu/ ID # 410

    Przemyśl, 37-700

  • Lubelskie Centrum Diagnostyczne/ ID # 402

    Świdnik, Lublin Voivodeship, 21-040

  • Specjalistyczny Gabinet Lekarski Krzysztof Dynowski / ID # 401

    Warsaw, 02-929

Other trials in Poland

Ukraine11 sites

  • City clinical maternity hospital №1/ ID # 502

    Chernivtsi, 58003

  • Ivano-Frankivsk regional perinatal center, Family planning center/ ID # 506

    Ivano-Frankivsk, 76018

  • Kyiv City Maternity Hospital #6/ ID # 504

    Kyiv, 02125

  • Medical center of LLC "Medical Center "Verum"/ ID # 503

    Kyiv, 03039

  • Institute of Pediatrics Obstetrics and Gynecology/ ID # 508

    Kyiv, 04050

  • Kyiv City Clinical Hospital #9/ ID # 501

    Kyiv, 04112

  • Kyiv City Center of Reproductive and Perinatal Medicine/ ID # 509

    Kyiv, 04210

  • Ternopil' Communal City Hospital#2 / ID # 511

    Ternopil, 46400

  • Vinnytsia City Clinical Hospital "Center of Mother and the Child "/ ID # 510

    Vinnytsia, 21019

  • Zaporizhzhya Regional Clinical Hospital/ ID # 505

    Zaporizhzhya, 69000

  • Maternity Hospital № 3/ ID # 507

    Zaporizhzhya, 69071

Other trials in Ukraine

United States8 sites

  • Chattanooga Medical Research LLC/ ID# 602

    Chattanooga, Tennessee, 37404

  • Choice Research, LLC/ ID # 609

    Dothan, Alabama, 36303

  • Universal Axon - Homestead, LLC/ ID # 620

    Homestead, Florida, 33030

  • Tanner Clinic/ ID # 624

    Layton, Utah, 84041

  • Southern Clinical Research / ID # 611

    Metairie, Louisiana, 70001

  • Advanced Specialty Research/ ID # 610

    Nampa, Idaho, 83687

  • Women's & Family Care, LLC dba GTC Research/ ID # 608

    Shawnee Mission, Kansas, 66218

  • Stedman Clinical Trials/ ID # 612

    Tampa, Florida, 33613

Other trials in United States

Romania6 sites

  • Quantum Medical Center SRL/ ID # 353

    Bucharest, 12071

  • Centrul Medical EUROMED/ ID # 351

    Bucharest, 20764

  • Spitalul Clinic "Nicolae Malaxa"/ ID # 352

    Bucharest, 22448

  • Sp Cl de Obstetrica si Ginecologie "Prof. Dr. Panait Sirbu"/ ID # 354

    Bucharest, 60251

  • Gine Plus SRL Cluj- Napoca/ ID # 357

    Cluj-Napoca, 400698

  • Centrul Medical GALENUS/ ID # 355

    Târgu Mureş, 540236

Other trials in Romania

Bulgaria5 sites

  • Multiprofile Hospital for Active Treatment Sliven/ ID # 131

    Sliven, 8800

  • MHAT Dr. Bratan Shukerov / ID #138

    Smolyan

  • Medical Centre Excelsior /ID # 135

    Sofia, 1407

  • Group Practice for Specialized Medical Assistance in GINART/ ID # 132

    Sofia, 1606

  • University Multiprofile Hospital for Active Treatment "Sofiamed"/ ID # 133

    Sofia, 1797

Other trials in Bulgaria

Czechia2 sites

  • Gynekologicko - Porodnicka Ambulance/ ID # 162

    Tábor, 39003

  • Gynekologie MU Dr.Lubomir Mikulasek / ID # 160

    Újezd nad Lesy, 19016

Other trials in Czechia

Spain2 sites

  • Hospital Regional Universitario de Málaga/ ID # 303

    Málaga, 29010

  • Hospital General Universitario Reina Sofia/ ID # 304

    Murcia, 30003

Other trials in Spain

Austria1 site

  • Salzburger Landeskliniken / ID # 105

    Salzburg, 5020

Other trials in Austria

France1 site

  • Clinique Pasteur / ID # 206

    Toulouse, 31076

Other trials in France

About this study

Official title: A Double-blind Randomized Extension Study to Assess the Long-term Efficacy and Safety of Linzagolix in Subjects With Endometriosis-associated Pain

The primary objective of this extension study is to assess the maintenance of efficacy of linzagolix administered orally once daily for up to an additional 6 months (for up to 12 months of treatment in total) in women who have already completed 6 months of linzagolix treatment at a dose of 75 mg alone or of 200 mg in combination with ABT (E2 1 mg / NETA 0.5 mg), in the management of moderate to severe endometriosis-associated pain (EAP) in women with surgically confirmed endometriosis.

Read the detailed description

This is a prospective, randomized, double-blind study. Subjects who have completed the 6-month Treatment Period in 18-OBE2109-003 - Edelweiss 3 study (herein referred to as main study) will be invited to enter the present extension study. Month 6 visit of the main study is a decision point for Subjects to either end treatment and enter a post-treatment follow up (part of the main study), or to opt for a 6-month treatment extension.

All subjects will receive once daily either linzagolix 75 mg alone (with ABT placebo) or 200 mg combined with ABT for 6 months. Subjects who received placebo during the main study will be randomized to either linzagolix 75 mg alone (with ABT placebo) or linzagolix 200 mg with ABT. Subjects who received active treatment during the main study will continue with the same treatment. Double-dummy design will be used in order to maintain the blinding of the study.

After end of treatment in the extension study (6-month treatment period: from Month 6 to Month 12), subjects will enter a post-treatment Follow-Up Period of 6 months with no investigational medicinal product (IMP) or - for subjects willing to continue treatment - a second extension study will be proposed.

Conditions
Endometriosis
Being tested
75 mg linzagolix tablet, 200 mg linzagolix tablet, Placebo tablet to match 75 mg linzagolix tablet, Placebo tablet to match 200 mg linzagolix tablet, Add-back capsule (E2 1 mg / NETA 0.5 mg)
Keywords
Dysmenorrhea, Dyspareunia, Dyschezia, Non-menstrual pelvic pain
Medical subject headings
Endometriosis, Dysmenorrhea, Dyspareunia, Constipation

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 75 mg linzagolix tabletDrug

    For oral administration once daily

  • 200 mg linzagolix tabletDrug

    For oral administration once daily

  • Placebo tablet to match 75 mg linzagolix tabletDrug

    For oral administration once daily

  • Placebo tablet to match 200 mg linzagolix tabletDrug

    For oral administration once daily

  • Add-back capsule (E2 1 mg / NETA 0.5 mg)Drug

    For oral administration once daily

  • Placebo capsule to match Add-back capsuleDrug

    For oral administration once daily

Study groups in NCT04335591
Study groupRoleWhat they receive
Linzagolix 75 mgExperimentalNot described
Receives: Drug: 75 mg linzagolix tablet; Drug: Placebo tablet to match 200 mg linzagolix tablet; Drug: Placebo capsule to match Add-back capsule
Linzagolix 200 mg + Add-back (E2 1 mg / NETA 0.5 mg)ExperimentalNot described
Receives: Drug: 200 mg linzagolix tablet; Drug: Placebo tablet to match 75 mg linzagolix tablet; Drug: Add-back capsule (E2 1 mg / NETA 0.5 mg)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Dysmenorrhea

    Proportion of subjects with reduction of DYS (Month 3 MCT) and stable or decreased use of analgesics for EAP at Month 12

    Measured: 6-month extension study treatment period (from Month 6 to Month 12)

  2. Non-menstrual Pelvic Pain

    Proportion of subjects with reduction of NMPP (Month 3 MCT) and stable or decreased use of analgesics for EAP at Month 12

    Measured: 6-month extension study treatment period (from Month 6 to Month 12)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted6 Apr 2020
  2. Study start5 Mar 2020
  3. Primary completion15 Sep 2022
  4. Study completion15 Dec 2022

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
356 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04335591
Sponsor's protocol ID
19-OBE2109-006
Status last verified
Mar 2024
First submitted
3 Apr 2020
Last updated
2 Apr 2025
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Publications

  • Donnez J, Becker CM, Petraglia F, Horne AW, Becker S, Renner SP, Carmona Herrera F, Taylor HS, Paszkowski M, Bestel E, Hori S, Dolmans MM. Linzagolix, with and without add-back therapy, in women with endometriosis-associated pain: results from EDELWEISS 6, a double-blind randomized extension and withdrawal study. Hum Reprod Open. 2026 Apr 8;2026(2):hoag030. doi: 10.1093/hropen/hoag030. eCollection 2026.

    PubMed 42077502

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing 75 mg linzagolix tablet, 200 mg linzagolix tablet and Add-back capsule (E2 1 mg / NETA 0.5 mg) in people with Endometriosis, run by Kissei Pharmaceutical Co., Ltd. at 47 sites in 9 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 2 Apr 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 47 sites in Poland, Ukraine, United States, Romania, Bulgaria and 4 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 30 Apr 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Dysmenorrhea (time frame: 6-month extension study treatment period (from Month 6 to Month 12)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04335591, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Apr 2025.

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