A Study of Romiplostim Plus Predniso(lo)ne vs. Predniso(lo)ne Alone for the Treatment of Previously Untreated Primary Immune Thrombocytopenia (ITP)

What Was Tested

In this phase 3 trial, researchers set out to test Romiplostim.

It had two arms (groups): Romiplostim + Predniso(lo)ne (experimental) and Predniso(lo)ne (active comparator).

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.

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.

The registry classes the interventions as drug.

Who Took Part

Enrollment: 126 planned participants were the target.

It was open to people of any sex aged from 18 years up to 100 years.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could 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: 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.

The full record lists 6 inclusion and 9 exclusion criteria; among the exclusions: life-threatening bleeding at randomization; uncontrolled hypertension before randomization; abnormal hepatic or renal function at screening.

How the Study Was Run

It was run as a randomized, parallel-group and open-label study.

Because people in this Romiplostim study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Groups ran in parallel: each of the participants stayed in one arm throughout.

Being open-label, the Romiplostim study did not mask who received what.

It started in 2026-08-21 with completion listed for 2029-09-14.

It ran at 3 sites in United States (3).

Its stated primary purpose is treatment.

What Was Measured

Primary outcome: Percentage of Participants With a Durable Platelet Response (DPR) (time frame: 8 weeks).

It also tracked 9 secondary outcomes, for example Time to Next Treatment (TTNT), Cumulative Exposure to Corticosteroids, Change From Baseline in ITP Patient Assessment Questionnaire (ITP-PAQ), Change in Summary Scores and Visual Analogue Scale (VAS) Scores per EuroQol 5-Dimension 5-Level (EQ 5D-5L), Incidence of Hospitalization and Rescue Medication in Part 1 and Serum Trough Concentration (Ctrough) of Romiplostim.

What This Means in Plain Language

Put simply, this is a phase 3, randomized trial of Romiplostim in 126 people.

It is still recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Romiplostim compound page, all human trials.