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
- Are there results?
- Not yet: the study is under way
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.
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- 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).
- ClinicalTrials.gov ID
- NCT07700238
- Acronym / sponsor ID
- ROMISTER / 20250124
- Conditions
- Primary Immune Thrombocytopenia
- Keywords
- Adult ITP
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 126 participants (estimated)
- Lead sponsor
- AmgenIndustry (pharma, biotech, devices)
- Study start
- 21 Aug 2026 (estimated)
- Primary completion
- 14 Sep 2029 (estimated)
- Study completion
- 14 Oct 2029 (estimated)
- First posted
- 13 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Romiplostim + Predniso(lo)ne | Experimental | Drug: Romiplostim, Drug: Predniso(lo)neParticipants 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. |
| Predniso(lo)ne | Active comparator | Drug: Predniso(lo)neParticipants 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. |
Who may qualify
- Ages
- 18 to 100 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- 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.
- Platelet count < 30 × 10^9/L or Platelet count < 50× 10^9/L with clinically significant bleeding before any medical intervention.
Key exclusion criteria (9 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| RomiplostimAlso: AMG 531, Nplate®Administered subcutaneously. | Drug | Romiplostim + Predniso(lo)ne |
| Predniso(lo)neAdministered orally. | Drug | Predniso(lo)ne, Romiplostim + Predniso(lo)ne |
Primary outcome
Percentage of Participants With a Durable Platelet Response (DPR)
Time frame: 8 weeks
9 secondary outcomes
Time to Next Treatment (TTNT)
Time frame: 12 months
Cumulative Exposure to Corticosteroids
Time frame: 12 months
Change From Baseline in ITP Patient Assessment Questionnaire (ITP-PAQ)
Time frame: 12 months
Change in Summary Scores and Visual Analogue Scale (VAS) Scores per EuroQol 5-Dimension 5-Level (EQ 5D-5L)
Time frame: 12 months
Incidence of Hospitalization and Rescue Medication in Part 1
Time frame: 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
Time frame: 12 months
Percentage of Participants With Clinically Significant Bleeding Events in the Immune Thrombocytopenia-specific Bleeding Assessment Tool (ITP-BAT)
Time frame: 6 months
Serum Trough Concentration (Ctrough) of Romiplostim
Time frame: 6 months
Number of Participants With Anti-Romiplostim Antibodies and Anti-Thrombopoietin (TPO) Antibodies
Time frame: 6 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2026.
- AmgenTrials clinical trials websiteLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. De-identified individual patient data for variables necessary to address the specific research question in an approved data sharing request.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
MD study director
Amgen
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
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.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 17 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Amgen Call Center (866-572-6436, medinfo@amgen.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of Participants With a Durable Platelet Response (DPR) (time frame: 8 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Sep 2026.