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ORPHA:3318

Essential thrombocythemia

medium confidenceDisorder

Also known as: ET · Essential thrombocytosis

Publications

10,580

95.3th percentile

Trials

157

Interventional, condition-specific

Researchers

1,276

Distinct authors in sample

Gene link

—

Readiness

5/6

Stages with a signal

Clinical definition (Orphanet)

Essential thrombocythemia (ET) is a myeloproliferative neoplasm (MPN) characterized by a sustained elevation of platelet number (> 450 x 109/L) with a tendency for thrombosis and hemorrhage.

How rare: 1-5 / 10 000 — about one to five people per ten thousand (still uncommon, but less ultra-rare).

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (5)

essential thrombocytemia · essential thrombocythemia · essential thrombocytosis · primary thrombocythemia · primary thrombocytosis

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.”

5/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    10,580 matched papers (5,862 in last 10 years) Source

  3. Phenotype characterisedPresent

    30 HPO annotations (e.g. Abnormal bleeding; Abnormality of thrombocytes; Increased megakaryocyte count) Source

  4. Animal modelPresent

    5 genotype models (Mus musculus) Source

  5. Orphan designationPresent

    3 FDA designations (2 FDA orphan-indication approvals) — e.g. ruxolitinib phosphate Source

  6. Interventional trialPresent

    157 matched on ClinicalTrials.gov (26 recruiting in sample)

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)

30

Associated phenotypes · MONDO:0005029

  • Abnormal bleeding
  • Abnormality of thrombocytes
  • Increased megakaryocyte count
  • Abnormal bone marrow cell morphology
  • Insomnia

Showing 5 of 30 — open Monarch for the full list.

Animal models (Monarch / Alliance)

5

Model associations linked to this Mondo ID

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)

3

Designations · 2 with FDA orphan-indication approval

  • FDA ruxolitinib phosphateESSENTIAL THROMBOCYTHEMIA · 2010-03-22 · Not FDA Approved for Orphan Indication
  • FDA pacritinibPrimary Myelofibrosis Myelofibrosis Polycythemia Vera ESSENTIAL THROMBOCYTHEMIA · 2008-03-13 · Not FDA Approved for Orphan Indication
  • FDA Anagrelide (Agrylin)ESSENTIAL THROMBOCYTHEMIA · 1988-01-27

Sources: FDA OOPD · EMA orphan designations

Open Targets candidates

33

Drugs / clinical candidates · MONDO_0005029

CTD chemicals (MyDisease.info)

11 associated chemicals · 242 pathways. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • anagrelide · therapeutic
  • Aspirin · therapeutic
  • Busulfan · therapeutic
  • Clopidogrel · therapeutic
  • Hydroxyurea · therapeutic
  • Imatinib Mesylate · therapeutic
  • Interferon-alpha · therapeutic
  • Melphalan · therapeutic
  • Pipobroman · therapeutic
  • Thiotepa · therapeutic
  • Uracil Mustard · therapeutic

Pathways: EGFR tyrosine kinase inhibitor resistance; MAPK signaling pathway; Ras signaling pathway; Rap1 signaling pathway; Cytokine-cytokine receptor interaction; Chemokine signaling pathway; FoxO signaling pathway; Phospholipase D signaling pathway

MyDisease.info · MONDO:0005029

Literature

Is anyone studying this?

10,580

10,580 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

10,580 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).

5,862 in the last 10 years · medium confidence · 95.3th percentile (publications denominator)

Phrase hits: 10,580 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,276

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Vannucchi AM10 papers · 2026

    Department of Experimental and Clinical Medicine, CRIMM, Center Research and Innovation of Myeloproliferative Neoplasms, Azienda Ospedaliera Universitaria Careggi, University of Florence, Florence, Italy.

    Papers in Europe PMC
  2. 02
    Guglielmelli P8 papers · 2026

    Department of Experimental and Clinical Medicine, CRIMM, Center Research and Innovation of Myeloproliferative Neoplasms, Azienda Ospedaliera Universitaria Careggi, University of Florence, Florence, Italy.

    Papers in Europe PMC
  3. 03
    Tefferi A8 papers · 2026

    Division of Hematology, Mayo Clinic, Rochester, MN, USA.

    Papers in Europe PMC
  4. 04
    Loscocco GG7 papers · 2026

    Department of Experimental and Clinical Medicine, CRIMM, Center Research and Innovation of Myeloproliferative Neoplasms, Azienda Ospedaliera Universitaria Careggi, University of Florence, Florence, Italy.

    Papers in Europe PMC
  5. 05
    Gangat N6 papers · 2026

    Division of Hematology, Mayo Clinic, Rochester, MN, USA.

    Papers in Europe PMC
  6. 06
    Barbui T5 papers · 2026

    FROM Research Foundation, Papa Giovanni XXIII Hospital, Bergamo, Italy.

    Papers in Europe PMC
  7. 07
    Zhang L5 papers · 2026

    State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.

    Papers in Europe PMC
  8. 08
    Caballero-Navarro G4 papers · 2026

    Hospital Universitario Miguel Servet, Zaragoza, Spain.

    Papers in Europe PMC
  9. 09
    Carreño-Tarragona G4 papers · 2026

    Hospital Universitario 12 de Octubre, Madrid, Spain.

    Papers in Europe PMC
  10. 10
    Chen MC4 papers · 2026

    Department of Public Health and Biostatistics Consulting Center, College of Medicine, Chang Gung University, No. 259 Wenhua 1st Road, Guishan District, Taoyuan 333, TaiwanDivision of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

157

interventional trials for this specific condition

157 interventional trials matched this specific condition name; 26 currently recruiting in our sample.

Data as of 11 September 2026

157 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 99.1th percentile).

medium confidence · 99.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

157 interventional trials matched after quoted-phrase search and title/condition post-filter.

Observational and natural-history studies

34 observational studies match this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.

Recruiting or not-yet-recruiting

Open the complete matched search on ClinicalTrials.gov

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 26 · after dedupe 26 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 26 · dropped 0 · fetched 2026-07-29

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 (26)

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 Essential thrombocythemia — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

This 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.

"Essential thrombocythemia" OR "Essential thrombocytosis" OR "essential thrombocytemia" OR "primary thrombocythemia" OR "primary thrombocytosis"

Run this search on Europe PMC

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Essential thrombocythemia" OR "Essential thrombocytosis" OR "essential thrombocytemia" OR "primary thrombocythemia" OR "primary thrombocytosis"

Interventional trials matched via: phrase (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 157 interventional · 34 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

Synonyms dropped by stoplist: ET

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • 1 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-26T22:51:13.365Z