What the trial was testing
The SPIRIT 1 enrolled 638 patients with endometriosis. The study was sponsored by Myovant Sciences and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.
What the results showed
~75% had a meaningful drop in period pain at 24 weeks.
The Lancet · 2022 · NCT03204318
These findings — that had a meaningful drop in period pain on relugolix combination at 24 weeks — were published in the The Lancet and represent the headline result of the study.
Researchers tracked outcomes across 638 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.
What this means for patients
For patients with endometriosis, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.
What you can do now
Relugolix combination therapy (Myfembree) is FDA-approved for moderate-to-severe endometriosis pain in pre-menopausal women and available now. It is a once-daily pill — no injections. Treatment is generally limited to two years because of bone-density concerns. Ask your gynecologist whether it is right for you.
Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.
Open endometriosis trials
Impact of Endotest on Patients' Quality of Life: a Cohort Study
Ziwig Endotest® ('Endotest') is marketed in several countries, including Switzerland, which was the first country to make it available in 2022. Since February 2025, several French clinical investigation sites have been offering Endotest, developed by Ziwig, under the innovation funding. Initially, this innovation funding enabled 2,500 patients to be included in a clinical trial (ENDOBEST: ID-RCB 2024-A02092-45). Since the end of December 2025, it has been expanded and now covers a further 22,500 patients whose are not included in the trial. This medical device is based on Next-Generation Sequencing combined with analytical algorithms and enables the identification of endometriosis from a saliva sample. This non-invasive test aims to improve patient care by reducing diagnostic delays and guiding treatment strategies. Despite the available data on its diagnostic performance, the impact of Endotest on patients' quality of life, their emotional experience, their coping strategies, and their care pathways remains insufficiently documented. Indeed, the Endotest result (positive or negative) can significantly influence these various aspects. This cohort study aims to assess the impact of Endotest on patients' quality of life, primarily using validated self-report questionnaires and clinical data from medical records. By including a large sample of patients, this study aims to provide robust and generalisable data that will be useful for clinicians and patients themselves.
Study of the Prevalence of Endometriosis and Adenomyosis
Our study aims to assess the prevalence of adenomyosis and endometriosis in patients consulting for elective fertility preservation through the diagnosis of these pathologies by transvaginal pelvic ultrasound. Imaging data will be compared with clinical data (patient characteristics, clinical symptoms) as well as the assessment of anxiety, depression, and quality of life collected from the women.