ORPHA:529831
Letrozole toxicity
Publications
6
16.4th percentile
Trials
0
Interventional, condition-specific
Researchers
29
Distinct authors in sample
Gene link
—
Readiness
1/6
Stages with a signal
How rare: How common this is has not been clearly measured.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0035350
- UMLS:C5681461
Research stages
Trial readiness signals
Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”
1/6 stages with a signal
Research-stage checklist from open sources (GenCC, literature, Monarch when enriched, ClinicalTrials.gov). Not a prognosis or care recommendation.
- Gene identifiedNot found
No GenCC disease–gene assertion in this build
- LiteraturePresent
6 matched papers (3 in last 10 years) Source
- Phenotype characterisedNot found
No HPO disease–phenotype associations via Monarch for these Mondo IDs
- Animal modelNot found
No Alliance genotype “model of” associations via Monarch for these Mondo IDs
- Orphan designationNot found
No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source
- Interventional trialNot found
No matched interventional trial under our ClinicalTrials.gov rules
Biology
Genes and phenotypes
Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.
Do we know what causes it?
Not yet — the cause hasn't been pinned down in GenCC.
No strong gene–disease assertion joined for this Orphanet entity.
Phenotypes (Monarch / HPO)
None returned for this Mondo ID. That often means “not linked under this ID,” not “no clinical features.”
Animal models (Monarch / Alliance)
None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.
Monarch fetch 2026-07-29
Therapies
Designations, candidates, and chemicals
FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.
Orphan designation (FDA · EMA)
No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.
Open Targets candidates
No drugs or clinical candidates returned for this Mondo ID on Open Targets.
CTD chemicals (MyDisease.info)
No CTD chemical associations returned for this Mondo ID.
Literature
Is anyone studying this?
6
6 papers have ever been indexed under this name. For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.
6 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).
3 in the last 10 years · high confidence · 16.4th percentile (publications denominator)
Phrase hits: 6 · MeSH hits: 0
Who's working on it?
29
Distinct author names in 6 sampled papers — named people below.
Who's working on it?
No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.
- 01Jonat W2 papers · 2008
Clinic for Gynecology and Obstetrics, University of Kiel, 24105 Kiel, Germany. jonat@email.uni-kiel.de
Papers in Europe PMC - 02Brufsky AM1 paper · 2017
Women's Cancer Research Center, Magee-Womens Research Institute, Pittsburgh, PA, USA.
Papers in Europe PMC - 03Cui MK1 paper · 2019
Department of Breast Surgery, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, China.
Papers in Europe PMC - 04Ford GR1 paper · 2022
Institute for Cellular and Molecular Medicine, Department of Medical Immunology, University of Pretoria, Pretoria 0002, South Africa.
Papers in Europe PMC - 05Gyanchandani R1 paper · 2017
Women's Cancer Research Center, Magee-Womens Research Institute, Pittsburgh, PA, USA.
Papers in Europe PMC - 06Hilpert F1 paper · 2006Papers in Europe PMC
- 07Jonnalagadda AR1 paper · 2017
Women's Cancer Research Center, Magee-Womens Research Institute, Pittsburgh, PA, USA.
Papers in Europe PMC - 08Joubert F1 paper · 2022
Center for Bioinformatics and Computational Biology, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa.
Papers in Europe PMC - 09Knapick BA1 paper · 2017
Women's Cancer Research Center, Magee-Womens Research Institute, Pittsburgh, PA, USA.
Papers in Europe PMC - 10Kota KJ1 paper · 2017
University of Pittsburgh Medical Center (UPMC) Presbyterian, University of Pittsburgh, Pittsburgh, PA, USA.
Papers in Europe PMC
Clinical research
Is a treatment being tested?
0
interventional trials for this specific condition
No interventional trial testing a treatment matched this specific condition name on ClinicalTrials.gov (observational studies and pan-disease registries are listed separately when present).
Data as of 11 September 2026 · last trial check 11 September 2026
No matched interventional trials. This is true for 77.2% of diseases in the trials denominator (5501 of 7126). Here are the researchers publishing on it.
high confidence · 38.6th percentile (trials denominator)
Recruiting interventional trials
From the matched ClinicalTrials.gov set
No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.
See who's working on it — people publishing on this disease are often the practical next contact when no trial is listed.
Other registries (secondary)
Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.
raw 6 · after dedupe 6 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 6 · dropped 0 · fetched 2026-07-30
Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri
No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).
Uncertain / not reviewed (6)
- isrctn·ISRCTN11948182·No longer recruiting·Using a mixed probiotic/prebiotic supplement (MBR-01) to help prevent diarrhea in patients taking abemaciclib for early breast cancer
skipped — LLM skipped (--skip-llm)
- isrctn·ISRCTN67316571·Recruiting·A study to assess the safety and effectiveness of inavolisib plus a cdk4/6 inhibitor and letrozole versus placebo plus a CDK4/6 inhibitor and letrozole in participants with advanced breast cancer
skipped — LLM skipped (--skip-llm)
- isrctn·ISRCTN37422164·No longer recruiting·Combination treatment for early hormone-positive HER-positive breast cancer
skipped — LLM skipped (--skip-llm)
- isrctn·ISRCTN13663157·No longer recruiting·Fulvestrant and vandetanib in advanced aromatase inhibitor resistant breast cancer
skipped — LLM skipped (--skip-llm)
- isrctn·ISRCTN72153214·No longer recruiting·A randomised study evaluating the efficacy and safety of sorafenib compared to placebo in metastatic breast cancer
skipped — LLM skipped (--skip-llm)
- isrctn·ISRCTN15692114·No longer recruiting·Endocrine treatment with letrozole, with or without local 3D conformal radiotherapy (3DCRT) of metastatic lesions in postmenopausal patients with inoperable, hormone-sensitive, oligometastatic breast cancer: a multicentre, randomised phase II study
skipped — LLM skipped (--skip-llm)
Where to find support
Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.
Orphanet entry for Letrozole toxicity — check Associations / patient organisations on that page.
India — NPRD
Last verified 2026-07-26This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.
Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.
How we counted this
Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.
"Letrozole toxicity"
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Letrozole toxicity"
Study-type breakdown: 0 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.
Query health: ok — strategies attempted: phrase; with hits: phrase
Run this search on ClinicalTrials.gov
Confidence reasoning
- Preferred label is multi-word and distinctive
- No synonyms dropped by stoplist
- No label/synonym collisions with other diseases in this corpus
Ingested 2026-07-27T18:06:57.154Z