A Study Evaluating the Safety and Efficacy of Long-term Dosing of Romiplostim in Thrombocytopenic Pediatric Patients With Immune (Idiopathic) Thrombocytopenia Purpura

An Open Label Study Evaluating the Safety and Efficacy of Long-term Dosing of Romiplostim in Thrombocytopenic Pediatric Subjects With Immune (Idiopathic) Thrombocytopenia Purpura (ITP)

This is an extension study designed to assess the safety and durability of platelet count increases with romiplostim treatment of thrombocytopenic patients with immune (Idiopathic) thrombocytopenia purpura. This study is available to pediatric patients who have completed a previous romiplostim ITP study and meet the eligibility criteria of this study.

Study Overview

• Status: Completed
• Conditions: Thrombocytopenia in Pediatric Subjects With Immune Idiopathic Thrombocytopenic Purpura ITP
• Intervention / Treatment: Biological: Romiplostim

• Study Type: Interventional
• Enrollment (Actual): 66
• Phase: Phase 3

Contacts and Locations

Study Locations

• Australia
  • New South Wales
    • Randwick, New South Wales, Australia, 2031
      • Research Site
  • Queensland
    • South Brisbane, Queensland, Australia, 4101
      • Research Site
  • Victoria
    • Parkville, Victoria, Australia, 3052
      • Research Site
• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5G 1X8
      • Research Site
  • Quebec
    • Montreal, Quebec, Canada, H4A 3J1
      • Research Site
    • Montreal, Quebec, Canada, H3T 1C5
      • Research Site
• Spain
  • Cataluña
    • Barcelona, Cataluña, Spain, 08035
      • Research Site
• United States
  • California
    • Orange, California, United States, 92868
      • Research Site
    • San Diego, California, United States, 92123
      • Research Site
  • District of Columbia
    • Washington, District of Columbia, United States, 20010
      • Research Site
  • Georgia
    • Atlanta, Georgia, United States, 30322
      • Research Site
  • Illinois
    • Chicago, Illinois, United States, 60611
      • Research Site
    • Peoria, Illinois, United States, 61615
      • Research Site
  • Indiana
    • Indianapolis, Indiana, United States, 46260
      • Research Site
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • Research Site
  • Kentucky
    • Louisville, Kentucky, United States, 40202
      • Research Site
  • Louisiana
    • New Orleans, Louisiana, United States, 70118
      • Research Site
  • Michigan
    • Detroit, Michigan, United States, 48201
      • Research Site
  • Missouri
    • Kansas City, Missouri, United States, 64108
      • Research Site
  • Nebraska
    • Omaha, Nebraska, United States, 68114
      • Research Site
  • Nevada
    • Las Vegas, Nevada, United States, 89109
      • Research Site
  • New Jersey
    • New Brunswick, New Jersey, United States, 08901
      • Research Site
  • New York
    • New York, New York, United States, 10016
      • Research Site
    • New York, New York, United States, 10021
      • Research Site
  • Ohio
    • Cincinnati, Ohio, United States, 45229
      • Research Site
    • Columbus, Ohio, United States, 43205
      • Research Site
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15224
      • Research Site
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Research Site
  • Texas
    • Dallas, Texas, United States, 75390
      • Research Site
    • Fort Worth, Texas, United States, 76104
      • Research Site
    • Houston, Texas, United States, 77030
      • Research Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 year and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Subject or subject's legally acceptable representative has provided informed consent.
• Subject completed a romiplostim study for the treatment of thrombocytopenia in pediatric subjects with ITP.

Exclusion Criteria:

• Subject has or previously had any 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).
• Subject has any new active malignancy diagnosed since enrollment in the previous romiplostim ITP study.
• Subject received any alkylating agents within four weeks before the screening visit or anticipated use during the time of the proposed study.
• Other investigational medications are excluded.
• Currently enrolled in another investigational device or drug study, or less than 30 days since ending another investigational device or drug study(s), or receiving other investigational agent(s) (with the exception of romiplostim in a previous clinical study).
• Female subject of child bearing potential (defined as having first menses) is not willing to use highly effective contraception during treatment and for 4 weeks after the end of treatment.
• Female subject is pregnant or breast feeding, or planning to become pregnant within 4 weeks after the end of treatment.
• Subject has known sensitivity to any of the products to be administered during dosing.
• Subject previously has entered this study (this will depend on the type of study).
• Subject will not be available for protocol required study visits, to the best of the subject and investigator's knowledge.
• Subject has any kind of disorder that, in the opinion of the investigator, may compromise the ability of the subject to give written informed consent and/or to comply with all required study procedures.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• 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; Participants received romiplostim administered by subcutaneous injection once a week. The starting dose of romiplostim was 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 between 50 x 10^9/L and 200 x 10^9/L.	Biological: Romiplostim; Administered by subcutaneous injection once a week.; Other Names: Nplate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Adverse Events	The adverse event (AE) severity grading scale used was the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 grading scale, where Grade 1 = Mild AE; Grade 2 = Moderate AE; Grade 3 = Severe AE; Grade 4 = Life-threatening or disabling AE; Grade 5 = Death related to AE. A serious adverse event was defined as an adverse event that met at least one of the following serious criteria: fatal; life threatening (places the subject at immediate risk of death); required in-patient hospitalization or prolongation of existing hospitalization; resulted in persistent or significant disability/incapacity; congenital anomaly/birth defect; other medically important serious event. The investigator assessed whether each adverse event was possibly related to the investigational product.	From first dose of study drug until 1 week after last dose. The median (minimum, maximum) duration of treatment was 135.0 weeks (5, 363 weeks).
Duration Adjusted Rate of Treatment Emergent Adverse Events	Exposure adjusted rate was defined as the total number of events divided by the duration of time participants were under observation. The adverse event (AE) severity grading scale used was the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 grading scale, where Grade 1 = Mild AE; Grade 2 = Moderate AE; Grade 3 = Severe AE; Grade 4 = Life-threatening or disabling AE; Grade 5 = Death related to AE. A serious adverse event was defined as an adverse event that met at least one of the following serious criteria: fatal; life threatening (places the subject at immediate risk of death); required in-patient hospitalization or prolongation of existing hospitalization; resulted in persistent or significant disability/incapacity; congenital anomaly/birth defect; other medically important serious event. The investigator assessed whether each adverse event was possibly related to the study drug.	From first dose of study drug until 1 week after last dose. The median (minimum, maximum) duration of treatment was 135.0 weeks (5, 363 weeks).
Number of Participants Who Developed Antibodies to Romiplostim	Two validated assays were used to test for antibodies to romiplostim / the thrombopoietin-mimetic peptide component of romiplostim (TMP). The first was an immunoassay to confirm the presence of antibodies. The second was a cell-based bioassay to detect neutralizing or inhibitory effects in vitro. If a sample was positive in both assays, a participant was defined as positive for neutralizing antibodies. Transient antibodies are those positive post-baseline but negative at the last time point tested. Persistent antibodies were those positive at the last time point tested.	Once a year until the end of treatment and 1 week after the end of treatment; median (minimim, maximum) time on study was 34 (2, 91) months.
Number of Participants Who Developed Antibodies to Endogenous Thrombopoietin	Two validated assays were used to test for antibodies to endogenous thrombopoietin (TPO). The first was an immunoassay to confirm the presence of antibodies. The second was a cell-based bioassay to detect neutralizing or inhibitory effects in vitro. If a sample was positive in both assays, a participant was defined as positive for neutralizing antibodies. Transient antibodies are those positive post-baseline but negative at the last time point tested. Persistent antibodies were those positive at the last time point tested.	Once a year until the end of treatment and 1 week after the end of treatment; median (minimim, maximum) time on study was 34 (2, 91) months.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants With a Platelet Response	Platelet response was defined as at least one platelet count ≥ 50 x 10^9/L in the absence of rescue medication during the study.	Assessed every 4 weeks for the duration of treatment; the median (minimum, maximum) duration of treatment was 135.0 weeks (5, 363 weeks).
Percentage of Participants Who Used Concomitant ITP Therapy		From baseline to the end of treatment; the median (minimum, maximum) duration of treatment was 135.0 weeks (5, 363 weeks).

Collaborators and Investigators

• Sponsor: Amgen

Publications and helpful links

General Publications

• Tarantino MD, Bussel JB, Blanchette VS, Beam D, Roy J, Despotovic J, Raj A, Carpenter N, Mehta B, Eisen M. Long-term treatment with romiplostim and treatment-free platelet responses in children with chronic immune thrombocytopenia. Haematologica. 2019 Nov;104(11):2283-2291. doi: 10.3324/haematol.2018.202283. Epub 2019 Mar 7.

Helpful Links

• AmgenTrials clinical trials website

Study record dates

Study Major Dates

• Study Start (Actual): December 30, 2009
• Primary Completion (Actual): January 12, 2017
• Study Completion (Actual): January 12, 2017

Study Registration Dates

• First Submitted: December 17, 2009
• First Submitted That Met QC Criteria: February 18, 2010
• First Posted (Estimate): February 19, 2010

Study Record Updates

• Last Update Posted (Actual): January 18, 2020
• Last Update Submitted That Met QC Criteria: January 7, 2020
• Last Verified: January 1, 2020

More Information

Terms related to this study

• Keywords: Pediatric; Thrombocytopenia; Immune thrombocytopenic Purpura
• Additional Relevant MeSH Terms: Pathologic Processes; Immune System Diseases; Autoimmune Diseases; Hematologic Diseases; Hemorrhage; Hemorrhagic Disorders; Blood Coagulation Disorders; Skin Manifestations; Blood Platelet Disorders; Thrombotic Microangiopathies; Purpura; Purpura, Thrombocytopenic; Purpura, Thrombocytopenic, Idiopathic; Thrombocytopenia
• Other Study ID Numbers: 20090340; 2009-016203-32 (EudraCT Number)