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Safety and Efficacy Study of Romiplostim to Treat Immune Thrombocytopenia (ITP) in Pediatric Patients

This study has been completed.
Information provided by (Responsible Party):
Amgen Identifier:
First received: September 29, 2011
Last updated: February 7, 2017
Last verified: February 2017
The purpose of this study is to evaluate the efficacy of romiplostim in the treatment of thrombocytopenia in pediatric patients with Immune thrombocytopenia purpura (ITP) as measured by durable platelet response.

Condition Intervention Phase
Idiopathic Thrombocytopenic Purpura
Thrombocytopenia in Pediatric Subjects With Immune (Idiopathic) Thrombocytopenic Purpura (ITP)
Thrombocytopenia in Subjects With Immune (Idiopathic) Thrombocytopenic Purpura (ITP)
Thrombocytopenic Purpura
Immune Thrombocytopenia
Drug: Romiplostim
Drug: Placebo
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Participant, Investigator, Outcomes Assessor
Primary Purpose: Treatment
Official Title: A Phase 3 Randomized, Double Blind, Placebo Controlled Study to Determine the Safety and Efficacy of Romiplostim in Thrombocytopenic Pediatric Subjects With Immune Thrombocytopenia (ITP)

Resource links provided by NLM:

Further study details as provided by Amgen:

Primary Outcome Measures:
  • Percentage of Participants With a Durable Platelet Response [ Time Frame: Week 18 to week 25 ]
    A participant with durable platelet response was defined as achieving at least 6 weekly platelet counts of ≥ 50 x 10^9/L during the last 8 weeks of treatment (platelet counts obtained from week 18 to week 25). If a platelet count from a participant was not available (missing) in a certain week, that week was imputed as non-response for that participant. Platelet counts were not deemed as a positive response for 4 weeks after the administration of rescue medication.

Secondary Outcome Measures:
  • Percentage of Participants With an Overall Platelet Response [ Time Frame: Week 2 to week 25 ]

    Overall platelet response is defined as either a durable platelet response or transient platelet response.

    Durable platelet response was defined as weekly platelet count ≥ 50 x 10^9/L for 6 or more times during week 18 to week 25 measurements. Participants may not have had a weekly response within 4 weeks after receiving any rescue medication.

    Transient platelet response was defined as weekly platelet count ≥ 50 x 10^9/L for 4 or more times during week 2 to week 25 measurements but without durable platelet response. Participants may not have had a weekly response within 4 weeks after receiving any rescue medications.

  • Number of Weeks With Platelet Response [ Time Frame: Week 2 to week 25 ]
    Number of weeks with platelet counts ≥ 50 x 10^9/L during week 2 to week 25 measurements. Participants may not have had a weekly response within 4 weeks after receiving any rescue medications.

  • Percentage of Participants Who Received Rescue Medication During the Treatment Period [ Time Frame: 24 weeks ]
    Rescue medication is any medication (other than excluded medications) that is intended to increase platelet counts or prevent bleeding.

  • Total Number of Composite Bleeding Episodes [ Time Frame: Week 2 to week 25 ]
    A composite bleeding episode was defined as clinically significant bleeding events or the use of a rescue medication to prevent a clinical significant bleeding event during weeks 2 through 25 of the treatment period. A clinically significant bleeding event was defined as a Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 grade ≥ 2 bleeding event.

  • Number of Participants With Adverse Events [ Time Frame: From the first dose of study drug until 4 weeks after last dose; 28 weeks. ]

    A serious adverse event is defined as an adverse event that meets at least 1 of the following serious criteria:

    • fatal,
    • life threatening (places the subject at immediate risk of death),
    • requires in-patient hospitalization or prolongation of existing hospitalization,
    • results in persistent or significant disability/incapacity,
    • congenital anomaly/birth defect, and/or
    • other significant medical hazard. Adverse events were graded for severity according to the CTCAE version 3.0 grading scale, where Grade 3 = moderate, Grade 4 = life-threatening and Grade 5 = fatal.

    Treatment-related adverse events (TRAEs) were those assessed by the investigator as possibly related to study drug. This relationship was determined by a "yes" or "no" response to the question: "Is there a reasonable possibility that the event may have been caused by study drug?"

Enrollment: 62
Study Start Date: January 2012
Study Completion Date: February 2015
Primary Completion Date: February 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Romiplostim
Participants received once weekly subcutaneous romiplostim for 24 weeks at a starting dose of 1 µg/kg; weekly dose increases continued in increments of 1 µg/kg/week to a maximum dose of 10 µg/kg in an attempt to reach a target platelet count of ≥ 50 x 10^9/L.
Drug: Romiplostim
The starting dose of romiplostim is 1 µg/kg administered weekly by subcutaneous injection. Participants will return to the clinic weekly to provide platelet counts and undergo dose titrations under the supervision of the treating physician. Weekly dose increases will continue in increments of 1 µg/kg up to a maximum dose of 10 µg/kg in an attempt to reach a target platelet count of ≥ 50 x 10^9/L. Dose adjustment will be allowed during the treatment period to maintain a platelet count between ≥ 50 x 10^9/L and ≤ 200 x 10^9/L.
Other Names:
  • AMG 531
  • Nplate®
Placebo Comparator: Placebo
Participants received weekly subcutaneous placebo for 24 weeks.
Drug: Placebo
Matching placebo administered by subcutaneous injection


Ages Eligible for Study:   1 Year to 17 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Diagnosis of primary ITP according to the American Society of Hematology (ASH) guidelines at least 6 months prior to screening, regardless of splenectomy status
  • Subject must be refractory to a prior ITP therapy, having relapsed after at least 1 prior ITP therapy, or ineligible for other ITP therapies; prior therapy includes first-line therapies
  • Age ≥ 1 year and < 18 years at the time of providing informed consent
  • The mean of 2 platelet counts taken during the screening period must be ≤ 30 x 10^9/L with neither count > 35 x 10^9/L
  • A serum creatinine concentration ≤ 1.5 times the laboratory normal range (for each age category) during the screening period
  • Adequate liver function; serum bilirubin ≤ 1.5 times the laboratory normal range during the screening period; aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3.0 times the laboratory normal range during the screening period
  • Hemoglobin > 10.0 g/dL during the screening period
  • Subject and/or subject's legally acceptable representative has provided informed consent prior to any study-specific procedure; subject has provided assent, where required

Exclusion Criteria:

  • Known history of a bone marrow stem cell disorder; any abnormal bone marrow findings other than those typical of ITP must be approved by Amgen before a subject may be enrolled in the study
  • Known active or prior malignancy except adequately treated basal cell carcinoma
  • Known history of congenital thrombocytopenia
  • Known history of hepatitis B, hepatitis C, or human immunodeficiency virus (HIV)
  • Known history of H. pylori by urea breath test or stool antigen test within 6 months of enrollment or successfully treated with no evidence of infection
  • Known history of systemic lupus erythematosus, evans syndrome, or autoimmune neutropenia
  • Known history of antiphospholipid antibody syndrome or positive for lupus anticoagulant
  • Known history of disseminated intravascular coagulation, hemolytic uremic syndrome, or thrombotic thrombocytopenic purpura
  • Previous history of venous thromboembolism or thrombotic events
  • Previous use of romiplostim, pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), Eltrombopag, recombinant human thrombopoietin (rHuTPO) or any platelet producing agent
  • Rituximab (for any indication) or 6-mercaptopurine (6-MP) within 14 weeks before the screening visit, or anticipated use during the time of the proposed study
  • Splenectomy within 4 weeks of the screening visit
  • All hematopoietic growth factors including interleukin-11 (IL-11) (oprelvekin) within 4 weeks before the screening visit
  • Alkylating agents within 8 weeks before the screening visit or anticipated use during the time of the proposed study
  • Vaccinations known to decrease platelet counts within 8 weeks before the screening visit
  • Known hypersensitivity to any recombinant E coli-derived product (eg, Infergen, Neupogen, Somatropin, and Actimmune)
  • Other criteria may apply
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01444417

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Sponsors and Collaborators
Study Director: MD Amgen
  More Information

Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Amgen Identifier: NCT01444417     History of Changes
Other Study ID Numbers: 20080279
2010-018426-39 ( EudraCT Number )
Study First Received: September 29, 2011
Results First Received: November 17, 2016
Last Updated: February 7, 2017

Keywords provided by Amgen:
Immune (Idiopathic) Thrombocytopenic Purpura
Pediatric Immune (Idiopathic) Thrombocytopenic Purpura
Immune Thrombocytopenia

Additional relevant MeSH terms:
Purpura, Thrombocytopenic, Idiopathic
Purpura, Thrombocytopenic
Blood Platelet Disorders
Hematologic Diseases
Blood Coagulation Disorders
Pathologic Processes
Skin Manifestations
Signs and Symptoms
Thrombotic Microangiopathies
Hemorrhagic Disorders
Autoimmune Diseases
Immune System Diseases processed this record on May 25, 2017