Estriol
| 證據等級: L5 | 預測適應症: 1 個 |
目錄
Estriol: From an Undocumented Original Indication to Amenorrhea
One-Sentence Summary
Estriol is a naturally occurring, weak estrogen; this dataset does not record its original approved indication or mechanism of action, and it is not currently marketed in Taiwan. The TxGNN model predicts potential efficacy for Amenorrhea (specifically functional hypothalamic amenorrhea, FHA) with a high model score of 99.18%, but the supporting evidence is currently thin: of 3 registered clinical trials, none directly support this drug-indication pair (two test a different compound, estetrol, and one was withdrawn), and of 13 publications identified, only one is a relevant interventional pilot study on estriol in FHA.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not documented in this dataset |
| Predicted New Indication | Amenorrhea (functional hypothalamic amenorrhea) |
| TxGNN Prediction Score | 99.18% |
| Evidence Level | L4 (mechanistic/preliminary studies only) |
| Market Status (Taiwan) | Not marketed |
| Number of Licenses | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available for estriol in this dataset. Based on known pharmacology, estriol is a naturally occurring, low-potency estrogen.
Functional hypothalamic amenorrhea (FHA) is driven by suppression of pulsatile GnRH release from the hypothalamus, resulting in a systemic hypoestrogenic state and loss of menstrual cycling. The repurposing hypothesis is that low-dose exogenous estriol could modulate hypothalamic-pituitary function — for example by altering LH secretion via negative feedback — and partially support recovery of the gonadal axis in FHA patients.
This is a plausible but indirect mechanistic link: it reflects a general pharmacological effect of estrogen replacement rather than an estriol-specific action, and no controlled trial has yet tested “resumption of menstrual cycling” as a primary endpoint. The prediction should therefore be treated as a research hypothesis rather than a clinically validated finding.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT04487392 | Phase 2 | Withdrawn | 0 | Tested photobiomodulation (not a drug) for postmenopausal vulvovaginal atrophy — unrelated intervention and indication, trial withdrawn with zero enrollment. Not usable as evidence. |
| NCT04090957 | Phase 3 | Completed | 1015 | E4Comfort Study II — tested estetrol (E4), a distinct compound from estriol (E3), for postmenopausal vasomotor symptoms. Unrelated to amenorrhea; appears to be a drug-name mismatch in the source data. |
| NCT04209543 | Phase 3 | Completed | 1570 | E4Comfort Study I — also tests estetrol, not estriol, for vasomotor symptoms. Same mismatch issue as above. |
None of the identified trials directly support estriol’s use in amenorrhea. All three are excluded on relevance review (wrong drug, wrong indication, or withdrawn/zero enrollment).
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 22137494 | 2012 | Cohort / interventional pilot study | Fertility and Sterility | Evaluated estriol administration’s effect on hypothalamic-pituitary function and gonadotropin (LH) secretion in women with functional hypothalamic amenorrhea. |
| 37371858 | 2023 | Review | Biomedicines | Reviews low-dose estrogens as neuroendocrine modulators in FHA, discussing the mechanism of impaired GnRH pulsatility and potential for restoring positive-feedback signaling. |
| 16526238 | 2005 | Cohort | Medicinski Pregled | Examines lipid and hormonal profiles in women with premature primary ovarian failure treated with estro-progestagens; relevant to hypoestrogenic amenorrhea but not estriol-specific. |
| 4102186 | 1971 | Case report / cohort | Lancet | Endocrinological findings in two patients with premature ovarian failure. |
| 2949864 | 1986 | Cohort | Zhong Xi Yi Jie He Za Zhi | Observational study on gonadal function changes in women with amenorrhea/oligomenorrhea (traditional Chinese medicine framework); limited direct relevance. |
| 7026111 | 1981 | Review | Clinical Obstetrics and Gynecology | Reviews hormonal contraception and neoplasia; only tangentially related. |
| 4254759 | 1971 | Review / case series | British Journal of Psychiatry | Discusses anorexia nervosa; not a direct estriol treatment study. |
| 5935707 | 1966 | Case report | American Journal of Obstetrics and Gynecology | Endocrine effects of medroxyprogesterone acetate during pregnancy — different drug. |
| 979592 | 1976 | Methodology | Die Medizinische Welt | Radioimmunoassay methodology for reproductive hormones including estriol; not a treatment study. |
| 1239569 | 1975 | Review | Rinsho Byori | Reviews hormone assay methods in obstetrics/gynecology; methodological, not treatment-focused. |
Only PMID 22137494 directly evaluates estriol treatment in FHA patients; the remainder are background, methodological, or indirectly related material.
Market Information
Estriol is not currently marketed in Taiwan — no drug licenses are on record (0 total). No original-indication or NDA data is available to summarize here.
Safety Considerations
TFDA label warnings, contraindications, and drug-interaction data for estriol are not currently available in this dataset (flagged as a Blocking data gap — this is required before any safety pre-screen can proceed). Please refer to the package insert for safety information once available.
Conclusion and Next Steps
Decision: Hold
Rationale: The mechanistic rationale for estriol in functional hypothalamic amenorrhea is biologically plausible but indirect, and is supported by only one relevant pilot study — none of the three registered clinical trials actually test this drug-indication pair. Combined with the absence of TFDA label/safety data (a Blocking gap for the S1 safety pre-screen) and the fact that estriol is not currently marketed in Taiwan, the evidence does not yet support proceeding.
To proceed, the following is needed:
- TFDA label warnings and contraindications (DG001, Blocking)
- Confirmed mechanism of action data from DrugBank or other authoritative source (DG002)
- Direct clinical trial evidence of estriol (not estetrol) in FHA/amenorrhea, ideally with menstrual-cycle resumption as an endpoint
- Clarification of Taiwan import/access pathway given current unmarketed status
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.