Romiplostim for Oral TPO-RA Resistant ITP

A Prospective Cohort Study of Romiplostim in Immune Thrombocytopenia Patients Resistant to Oral Thrombopoietin Receptor Agonists

This study is a prospective, multicenter, open-label, single-arm cohort study to evaluate the effectiveness and safety of romiplostim in patients with immune thrombocytopenia (ITP) who have not responded to oral thrombopoietin receptor agonists (TPO-RAs) such as eltrombopag, hetrombopag, or avatrombopag.

ITP is a blood disorder in which the immune system attacks and destroys the body's own platelets, leading to low platelet counts and an increased risk of bleeding. While oral TPO-RAs are effective for many patients, approximately 20-30% of patients do not respond adequately or lose response over time. For these patients, alternative treatments are urgently needed.

Participants in this study will discontinue their current oral TPO-RA and receive romiplostim as a weekly subcutaneous injection. The starting dose is 3 µg/kg, and the dose may be adjusted weekly based on platelet counts (maximum 10 µg/kg). The total treatment and follow-up period is 24 weeks.

The primary outcome measure is the durable platelet response rate at week 24, defined as maintaining platelet counts at ≥50×10⁹/L for at least two scheduled visits during weeks 22-24 without rescue therapy. Secondary outcomes include the sustained response rate at week 12, complete response rate at week 24, time to first response, improvement in bleeding events, and quality of life assessment.

Safety outcomes include monitoring for thromboembolic events, bone marrow fibrosis, hepatotoxicity, injection site reactions, and other adverse events according to CTCAE v5.0.

Approximately 60 participants will be enrolled across multiple centers in China. This study aims to provide evidence for romiplostim as a treatment option for ITP patients who have failed oral TPO-RAs.

Study Overview

• Status: Recruiting
• Conditions: Immune (Idiopathic) Thrombocytopenic Purpura (ITP)
• Intervention / Treatment: Drug: Romiplostim

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: The First Affiliated Hospital of Soochow University; Phone Number: 86-0512-67781521; Email: tianhong0718@163.com

Study Locations

• China
  • Jiangsu
    • Suzhou, Jiangsu, China, 215000
      • Recruiting
      • The First Affiliated Hospital of Soochow University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Age ≥18 years Diagnosed with primary immune thrombocytopenia (ITP) according to current guidelines

Failed prior oral TPO-RA therapy (eltrombopag, hetrombopag, or avatrombopag), defined as:

Platelet count persistently <30×10⁹/L after ≥4 weeks of treatment at the maximum recommended or tolerated dose, OR Prior achieved response (platelet ≥50×10⁹/L) then lost response with platelet count <30×10⁹/L on two consecutive visits (≥1 week apart), OR Intolerance to oral TPO-RA leading to discontinuation (with documented reason) Baseline platelet count <30×10⁹/L (at least two measurements, ≥5 days apart) ECOG performance status 0-2 Willing and able to receive weekly subcutaneous injections and comply with study procedures For women of childbearing potential: negative pregnancy test at screening and agreement to use effective contraception during the study and for 3 months after the last dose Able to provide written informed consent

Exclusion Criteria:

Secondary ITP (e.g., associated with autoimmune diseases, lymphoproliferative disorders, drug-induced, or infections such as HIV/HCV/HBV) Known hypersensitivity to romiplostim or any of its excipients Prior treatment with romiplostim Received rituximab or other B-cell depleting therapy within 6 months prior to screening Received immunosuppressants (e.g., cyclosporine, mycophenolate mofetil, azathioprine, danazol) within 4 weeks prior to screening Splenectomy within 8 weeks prior to screening Use of corticosteroids (prednisone >10 mg/day or equivalent) or IVIG within 2 weeks prior to screening History of bone marrow fibrosis (MF grade ≥2) or known reticulin fibrosis History of arterial or venous thromboembolic event (e.g., myocardial infarction, stroke, deep vein thrombosis, pulmonary embolism) within 6 months prior to screening Known thrombophilic conditions (e.g., antiphospholipid syndrome, protein C/S deficiency, ATIII deficiency) Severe hepatic impairment (ALT or AST >3×ULN, or total bilirubin >1.5×ULN) Severe renal impairment (creatinine clearance <30 mL/min) New York Heart Association (NYHA) functional class III or IV heart failure Malignancy within 5 years prior to screening (except non-melanoma skin cancer, cervical carcinoma in situ, or ductal carcinoma in situ of the breast) Pregnancy or breastfeeding Participation in another interventional clinical trial within 30 days prior to screening Any other condition that, in the investigator's judgment, would make the participant unsuitable for the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Romiplostim Treatment Arm

Drug: Romiplostim; Romiplostim is administered as a subcutaneous injection once weekly for 24 weeks. The starting dose is 3 µg/kg. Platelet count is assessed weekly, and the dose is adjusted based on platelet count and bleeding symptoms as follows: If platelet count <50×10⁹/L: increase dose by 1 µg/kg (maximum dose: 10 µg/kg per week) If platelet count 50-200×10⁹/L: maintain the lowest dose that reduces bleeding risk If platelet count 200-400×10⁹/L: decrease dose by 1 µg/kg If platelet count >400×10⁹/L: withhold dosing. After platelet count decreases to <200×10⁹/L, resume at a dose 1 µg/kg lower than the dose before withholding.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Durable Platelet Response Rate at Week 24	Defined as the proportion of participants achieving platelet count ≥50×10⁹/L for at least two scheduled visits during weeks 22-24, without receiving rescue therapy (IVIG, high-dose corticosteroids, or platelet transfusion) during weeks 20-24.	24 weeks

Collaborators and Investigators

• Sponsor: The First Affiliated Hospital of Soochow University
• Collaborators: The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School; Shanghai Tong Ren Hospital; The First People's Hospital of Changzhou; Affiliated Hospital of Nantong University; Zhangjiagang First People's Hospital; Soochow Hopes Hematonosis Hospital; Changshu Affiliated Hospital of Soochow University

Study record dates

Study Major Dates

• Study Start (Actual): March 15, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): June 1, 2028

Study Registration Dates

• First Submitted: May 21, 2026
• First Submitted That Met QC Criteria: May 21, 2026
• First Posted (Actual): May 28, 2026

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Immune Thrombocytopenia; Drug Resistance; Romiplostim; Thrombopoietin Receptor Agonists
• Additional Relevant MeSH Terms: Cytopenia; Pathologic Processes; Autoimmune Diseases; Immune System Diseases; Hemorrhage; Skin Manifestations; Hematologic Diseases; Blood Coagulation Disorders; Hemorrhagic Disorders; Blood Platelet Disorders; Thrombotic Microangiopathies; Purpura; Thrombocytopenia; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hemic and Lymphatic Diseases; Purpura, Thrombocytopenic, Idiopathic; Purpura, Thrombocytopenic; romiplostim
• Other Study ID Numbers: 20251200

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No