Primary Immune ThrombocytopeniaPhase 3ROMISTERNCT07700238
A Study of Romiplostim Plus Predniso(lo)ne vs. Predniso(lo)ne Alone for the Treatment of Previously Untreated Primary Immune Thrombocytopenia (ITP)
A Phase 3 study testing Romiplostim and Predniso(lo)ne in people with Primary Immune Thrombocytopenia, run by Amgen at 3 sites in United States.
Trial summary
This Phase 3 study is designed to evaluate the efficacy and safety of romiplostim in combination with predniso(lo)ne compared with predniso(lo)ne alone in adults with previously untreated Primary Immune Thrombocytopenia (ITP). Read more about this study
- Who is it for?
- Ages 18 to 100 years
- Conditions the study is for
- Primary Immune Thrombocytopenia
- What is being tested?
- Romiplostim and Predniso(lo)ne
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 126 participants
- Where
- 3 sitesUnited States
- Study dates
- 21 Aug 2026to 14 Oct 2029
- Phase
- Phase 3
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 100 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥18 years or adult legal age within country if older than 18 years.
- Diagnosis of primary ITP according to the 2019 International Consensus (ICR) that is previously untreated and requires treatment.
- Note: The investigator should ensure that the diagnosis of primary ITP is established by excluding other causes of isolated thrombocytopenia, as outlined in the 2019 ICR, which states that the diagnosis of primary ITP is principally based on the exclusion of other causes of isolated thrombocytopenia.
- Note: If emergency treatment is necessary, platelet count performed before emergency can be used for study inclusion.
- Note: Emergency ITP treatment with any thrombopoietin receptor agonists (TPO-RAs), or splenectomy is not allowed.
- Platelet count < 30 × 10^9/L or Platelet count < 50× 10^9/L with clinically significant bleeding before any medical intervention.
Who cannot join
- Life-threatening bleeding at randomization.
- Known sensitivity or intolerance to any of the products to be administered during study (eg, uncontrolled diabetes) or to any Escherichia coli-derived product (eg, filgrastim, pegfilgrastim, certain insulins).
- Uncontrolled hypertension before randomization.
- Abnormal hepatic or renal function at screening.
- History of total splenectomy.
- Use of concurrent anticoagulation therapy and/or antiplatelet therapy.
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- Need for nonsteroidal anti-inflammatory drugs (NSAIDs) use and use of NSAIDs within 7 days before randomization.
- Venous or arterial thrombotic event within 3 or 6 months, respectively, before randomization.
- Other protocol-defined Inclusion/Exclusion may apply.
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States3 sites, 3 recruiting
- Recruiting
Hematology Oncology Associates of Fredericksburg
Fredericksburg, Virginia, 22408
- Recruiting
MemorialCare Long Beach Medical Center
Long Beach, California, 90806
- Recruiting
The Bleeding and Clotting Disorders Institute
Peoria, Illinois, 61614
About this study
Official title: A Phase 3, Randomized, Multicenter, Open-label Study to Evaluate the Efficacy and Safety of Romiplostim Plus Predniso(lo)ne vs. Predniso(lo)ne Alone for the Treatment of Adults With Previously Untreated Primary Immune Thrombocytopenia (ITP).
This Phase 3 study is designed to evaluate the efficacy and safety of romiplostim in combination with predniso(lo)ne compared with predniso(lo)ne alone in adults with previously untreated Primary Immune Thrombocytopenia (ITP).
- Conditions
- Primary Immune Thrombocytopenia
- Being tested
- Romiplostim, Predniso(lo)ne
- Keywords
- Adult ITP
- Medical subject headings
- Purpura, Thrombocytopenic, Idiopathic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
RomiplostimDrug
Also called AMG 531, Nplate®
Administered subcutaneously.
Predniso(lo)neDrug
Administered orally.
| Study group | Role | What they receive |
|---|---|---|
| Romiplostim + Predniso(lo)ne | Experimental | Participants will receive romiplostim administered subcutaneously (SC) in combination with predniso(lo)ne administered orally during Part 1 of the study.
Participants who complete Part 1 of the study will enter Part 2 and continue participation for study assessments. Receives: Drug: Romiplostim; Drug: Predniso(lo)ne |
| Predniso(lo)ne | Active comparator | Participants will receive predniso(lo)ne administered orally during Part 1 of the study.
Participants who complete Part 1 of the study will enter Part 2 and continue participation for study assessments. Receives: Drug: Predniso(lo)ne |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of Participants With a Durable Platelet Response (DPR)
Measured: 8 weeks
Secondary outcomes (9)
Time to Next Treatment (TTNT)
Measured: 12 months
Cumulative Exposure to Corticosteroids
Measured: 12 months
Change From Baseline in ITP Patient Assessment Questionnaire (ITP-PAQ)
Measured: 12 months
Change in Summary Scores and Visual Analogue Scale (VAS) Scores per EuroQol 5-Dimension 5-Level (EQ 5D-5L)
Measured: 12 months
Incidence of Hospitalization and Rescue Medication in Part 1
Measured: 6 months
Number of Participants Experiencing Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious Adverse Events (TESAEs), Treatment-Emergent Adverse Events of Interest (EOI), and Fatal TEAEs
Measured: 12 months
Percentage of Participants With Clinically Significant Bleeding Events in the Immune Thrombocytopenia-specific Bleeding Assessment Tool (ITP-BAT)
Measured: 6 months
Serum Trough Concentration (Ctrough) of Romiplostim
Measured: 6 months
Number of Participants With Anti-Romiplostim Antibodies and Anti-Thrombopoietin (TPO) Antibodies
Measured: 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Jul 2026
- Study start21 Aug 2026 (estimated)
- Primary completion14 Sep 2029 (estimated)
- Study completion14 Oct 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Primary Immune ThrombocytopeniaStudies of the same condition, open and under way.
- More trials run by AmgenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 126 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Amgen
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- MD, Study director, Amgen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07700238
- Sponsor's protocol ID
- 20250124
- Acronym
- ROMISTER
- Status last verified
- Sep 2026
- First submitted
- 7 Jul 2026
- Last updated
- 17 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified individual patient data for variables necessary to address the specific research question in an approved data sharing request.