Norethisterone
| 證據等級: L5 | 預測適應症: 10 個 |
目錄
Norethisterone: From Hormonal Contraception/Menstrual Regulation to Amenorrhea
One-Sentence Summary
Norethisterone is a synthetic progestin with long-established clinical use in hormonal contraception and menstrual cycle regulation, including induction of withdrawal bleeding and management of secondary amenorrhea. The TxGNN model predicts it may be effective for Amenorrhea, with 8 clinical trials and 20 publications currently identified, though most evidence relates to norethindrone acetate as an “add-back” component in fibroid/heavy-menstrual-bleeding regimens rather than direct amenorrhea treatment.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not available from formal regulatory data (drug is not currently registered in Australia); established clinical use is hormonal contraception and menstrual cycle regulation |
| Predicted New Indication | Amenorrhea |
| TxGNN Prediction Score | 99.60% |
| Evidence Level | L4 |
| Australia Market Status | Not marketed |
| Number of ARTG Entries | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in this evidence pack (MOA marked as a data gap). Based on known pharmacology, norethisterone is a synthetic progestin that binds progesterone receptors in the endometrium, and is part of the broader progestin class used in hormonal contraceptives and menstrual-disorder therapy.
Norethisterone’s established uses — menstrual cycle regulation, induction of withdrawal bleeding, and treatment of secondary amenorrhea — mean the TxGNN-predicted link to “amenorrhea” largely reflects pharmacology that is already clinically recognised rather than a genuinely novel mechanistic insight. This is consistent with the rationale text accompanying the prediction, which notes the mechanism is “existing pharmacological knowledge rather than a new discovery.”
However, the clinical trial evidence retrieved for this specific disease term is mostly indirect: the majority of trials studied norethindrone acetate as a low-dose “add-back” component alongside GnRH antagonists (relugolix, elagolix) for heavy menstrual bleeding associated with uterine fibroids — a different clinical context from primary treatment of amenorrhea.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrolment | Key Findings |
|---|---|---|---|---|
| NCT03412890 | Phase 3 | Completed | 477 | LIBERTY Extension: long-term safety/efficacy of relugolix + estradiol + norethindrone acetate add-back for fibroid-related heavy menstrual bleeding (indirect relevance to amenorrhea) |
| NCT06953076 | N/A | Recruiting | 111 | Ultrasound imaging study of fibroid changes during relugolix-estradiol-norethisterone treatment; not an amenorrhea trial |
| NCT05620355 | Phase 3 | Unknown | 312 | BG2109 ± add-back therapy for heavy menstrual bleeding in uterine fibroids |
| NCT01441635 | Phase 2 | Completed | 271 | Elagolix (not norethisterone) for heavy uterine bleeding with fibroids |
| NCT01817530 | Phase 2 | Completed | 571 | Elagolix ± add-back therapy for fibroid-related heavy menstrual bleeding |
| NCT03049735 | Phase 3 | Completed | 388 | LIBERTY 1: relugolix ± low-dose estradiol/norethindrone acetate for fibroid-related heavy menstrual bleeding |
| NCT03751124 | Phase 3 | Completed | 229 | Randomized withdrawal study of relugolix + estradiol + norethindrone acetate, up to 104 weeks, in fibroid patients |
| NCT03103087 | Phase 3 | Completed | 382 | LIBERTY 2: relugolix ± low-dose estradiol/norethindrone acetate for fibroid-related heavy menstrual bleeding |
Note: All eight trials were graded “C” relevance — norethisterone/norethindrone acetate appears as a low-dose add-back agent alongside a GnRH antagonist, and the studied indication (heavy menstrual bleeding with uterine fibroids) is distinct from amenorrhea.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 37863160 | 2024 | RCT subgroup analysis | American Journal of Obstetrics and Gynecology | Relugolix + estradiol + norethindrone acetate improved fibroid-associated heavy menstrual bleeding over 52 weeks in Black/African American women |
| 6786825 | 1981 | Phase I clinical trial | Contraception | Norethisterone enanthate/acetate suppressed LH/FSH peaks; amenorrhea and menstrual disorders reported as treatment effects in 20 women |
| 38530848 | 2024 | RCT | PLoS One | Norethisterone enanthate vs. DMPA-IM injectable contraception: effects on estradiol levels and menstrual/behavioural measures |
| 23641480 | 2013 | Systematic review (Cochrane) | Cochrane Database of Systematic Reviews | Review of combination injectable contraceptives, including norethisterone-containing regimens, and bleeding-pattern effects |
| 18843662 | 2008 | Systematic review (Cochrane) | Cochrane Database of Systematic Reviews | Earlier Cochrane review of combination injectable contraceptives and menstrual effects |
| 37103532 | 2023 | Review | Obstetrics and Gynecology | Overview of oral GnRH antagonists co-administered with steroid hormones (including norethindrone acetate) for uterine leiomyomas |
| 2660092 | 1989 | Review | Pediatric Clinics of North America | General review of hormonal contraception principles for adolescents |
Australia Market Information
Norethisterone is currently not marketed in Australia — no ARTG entries were identified (0 licenses on record in this evidence pack). Formal approved-indication text is therefore not available; any clinical use would depend on future TGA registration or Special Access Scheme pathways.
Safety Considerations
Please refer to the TGA-approved Product Information (PI) for safety information. Key warnings, contraindications, and drug-drug interaction data were not available in this evidence pack (flagged as a Blocking data gap — DG001 — preventing safety pre-assessment).
Conclusion and Next Steps
Decision: Hold
Rationale:
- The predicted mechanism is biologically plausible and consistent with norethisterone’s known progestin pharmacology (already used clinically to manage secondary amenorrhea), but the identified evidence base is indirect — all 8 clinical trials studied norethindrone acetate as a low-dose add-back agent for fibroid-related heavy menstrual bleeding, not amenorrhea as a primary endpoint, and literature is dominated by reviews rather than direct RCTs.
- The drug is not currently registered in Australia (0 ARTG entries), and safety/warning data is entirely missing, which blocks any safety pre-assessment (S1).
To proceed, the following is needed:
- TGA Product Information / PI safety data (warnings, contraindications, drug interactions) — currently a blocking data gap
- Confirmed mechanism of action (MOA) data from DrugBank or equivalent source
- Trials or literature directly evaluating norethisterone monotherapy for amenorrhea (rather than as an add-back component)
- Regulatory pathway assessment given the drug’s current unregistered status in Australia
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.