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NCT Number: NCT07623200

A Phase 3 Study of INCA033989 Versus Best Available Therapy in Participants With Essential Thrombocythemia

This study is being conducted to evaluate INCA033989 versus best available therapy in participants with essential thrombocythemia and a CALR mutation previously treated with cytoreductive therapy.

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Key information

Conditions

Essential Thrombocythemia Blood Coagulation Disorders Blood Platelet Disorders Bone Marrow Diseases Hematologic Diseases Hemic and Lymphatic Diseases Hemorrhagic Disorders Myeloproliferative Disorders Thrombocythemia, Essential Thrombocytosis

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Confirmed diagnosis of high-risk ET.
  • Presence of mutCALR.
  • Prior treatment with at least 1 cytoreductive therapy.

Exclusion criteria

  • Presence of any hematologic malignancy other than ET.
  • Major bleeding or thrombosis within the last 3 months prior to study enrollment.
  • Any prior allogenic or autologous stem-cell transplantation.
  • Unresolved toxicity ≥ Grade 2 from previous therapy except for stable chronic toxicities (Grade 2) not expected to resolve, such as stable Grade 2 peripheral neuropathy.
  • Prior nonhematologic malignancy except for the following: Malignancy treated with curative intent and with no evidence of active disease for more than 2 years before screening. Adequately treated carcinoma in situ without current evidence of disease.

Other protocol-defined Inclusion/Exclusion Criteria apply.

Treatment and study plan

INCA033989

Drug

Administered intravenous (IV) in accordance with the protocol-defined requirements.

Best Available Treatment

Drug

Best Available Therapy (BAT) will be selected by the investigator.

Other names: BAT could include:, • HU, • ANA, • PEG interferon alfa-2a, • Ropeginterferon alfa-2b

Primary outcomes

  1. Durable clinicohematologic response (DCR)

    Time frame: Week 24

    Normalization of platelet and white blood cell (WBC) counts and absence of disease progression as defined in the protocol.

Secondary outcomes

  1. Reduction from baseline in calreticulin exon 9 frameshift mutation(s) (mutCLAR) variant allele frequency (VAF)

    Time frame: Week 24

    Reduction in mutCALR VAF as defined in the protocol.

  2. Durable clinicohematologic response (DCR)

    Time frame: Week 48

    Normalization of platelet and white blood cell (WBC) counts and absence of disease progression as defined in the protocol.

  3. Durable partial clinicohematologic response (DPR)

    Time frame: Week 24

    Improvement of platelet and white blood cell (WBC) counts and absence of disease progression as defined in the protocol.

  4. Durable partial clinicohematologic response (DPR)

    Time frame: Week 48

    Improvement of platelet and white blood cell (WBC) counts and absence of disease progression as defined in the protocol.

  5. Longest duration of complete hematologic response (CHR)

    Time frame: Up to Week 48

    Longest time from documented CHR until the loss of CHR as defined in the protocol.

  6. Number of Participants with Treatment Emergent Adverse Events (TEAE)

    Time frame: Up to Week 48 and 60 days after last dose

    Defined as any adverse event occurring after the first dose of study drug until up to 60 days after the last dose of study drug.

  7. TEAEs leading to dose interruptions, dose reductions or discontinuation of study treatment

    Time frame: Up to Week 48 and 60 days after last dose

    TEAEs leading to dose interruptions, dose reductions or discontinuation of study treatment.

  8. Number of participants with a reduction in mutCALR VAF

    Time frame: Week 24 and Week 48

    Number of participants with a reduction in mutCALR VAF as defined in the protocol.

  9. Molecular response

    Time frame: Week 24 and Week 48

    Overall reduction in mutCALR VAF as defined in the protocol.

  10. Change from baseline in Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) total symptom score (TSS)

    Time frame: Up to Week 48

    Defined as the proportion of participants who achieve a protocol defined reduction in TSS.

  11. Change from baseline in Brief Fatigue Inventory (BFI) fatigue score

    Time frame: Up to Week 48

    The BFI is a 9 item scored from 0 (no fatigue) -10 (as bad as you can imagine), items are averaged with total score from 0-10, with higher score indicating more fatigue.

  12. Patient Global Impression of Change (PGIC) score

    Time frame: Up to Week 48

    The PGIC is based on a 7-point scale and the participant will rate each question from the start of treatment as 1-very much improved, 2-much improved, 3-minimally improved, 4-no change, 5-minimally worse, 6-much worse, and 7-very much worse.

Study contacts

Contact information is provided by the study sponsor or research team.

Incyte Corporation Call Center (US)

CONTACT

[email protected]

1.855.463.3463

Incyte Corporation Call Center (ex-US)

CONTACT

[email protected]

+800 00027423

Sponsors and collaborators

Lead sponsor

Incyte Corporation

Industry

Registry information

Official study title

A Phase 3, Randomized, Open-Label Study of INCA033989 Versus Best Available Therapy in Participants With Essential Thrombocythemia and a CALR Mutation Previously Treated With Cytoreductive Therapy (EXCALIBUR-ET2)

Acronym: EXCALIBUR-ET2

Important dates

Study start
2026
Primary completion
2029
Study completion
2030
First posted
Jun 3, 2026
Registry last updated
Jun 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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