Long-term Study of Romiplostim in Thrombocytopenic Pediatric Patients With Immune Thrombocytopenia (ITP)

A Single Arm, Open-label, Long-term Efficacy and Safety Study of Romiplostim in Thrombocytopenic Pediatric Subjects With Immune Thrombocytopenia (ITP)

This is a phase 3b single arm, open label, multicenter study describing the percentage of time pediatric participants with ITP have a platelet response while receiving romiplostim, defined as a platelet count ≥ 50 x 10^9/L in the absence of ITP rescue medications for the past 4 weeks.

Study Overview

• Status: Completed
• Conditions: Immune Thrombocytopenia
• Intervention / Treatment: Drug: Romiplostim

• Study Type: Interventional
• Enrollment (Actual): 203
• 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
• Belgium
  • Brussels, Belgium, 1020
    • Research Site
  • Bruxelles, Belgium, 1200
    • Research Site
  • Gent, Belgium, 9000
    • Research Site
  • Leuven, Belgium, 3000
    • Research Site
  • Liege, Belgium, 4000
    • Research Site
• Brazil
  • Pará
    • Belem, Pará, Brazil, 66033-000
      • Research Site
  • São Paulo
    • Jau, São Paulo, Brazil, 17210-120
      • Research Site
    • Sao Paulo, São Paulo, Brazil, 05403-000
      • Research Site
    • Sao Paulo, São Paulo, Brazil, 08270-070
      • Research Site
• Canada
  • Ontario
    • Hamilton, Ontario, Canada, L8S 4K1
      • Research Site
    • Toronto, Ontario, Canada, M5G 1X8
      • Research Site
  • Quebec
    • Montreal, Quebec, Canada, H4A 3J1
      • Research Site
    • Montreal, Quebec, Canada, H3T 1C5
      • Research Site
• Czechia
  • Olomouc, Czechia, 775 20
    • Research Site
  • Ostrava-Poruba, Czechia, 708 52
    • Research Site
  • Praha 5, Czechia, 150 06
    • Research Site
• France
  • Montpellier cedex 05, France, 34295
    • Research Site
  • Nice Cedex 3, France, 06202
    • Research Site
  • Paris, France, 75019
    • Research Site
  • Vandoeuvre les Nancy, France, 54511
    • Research Site
• Hungary
  • Budapest, Hungary, 1094
    • Research Site
  • Debrecen, Hungary, 4032
    • Research Site
  • Szeged, Hungary, 6720
    • Research Site
• Israel
  • Beer Sheva, Israel, 84101
    • Research Site
  • Haifa, Israel, 31096
    • Research Site
  • Jerusalem, Israel, 91120
    • Research Site
  • Petach Tikvah, Israel, 49202
    • Research Site
  • Tel Aviv, Israel, 64239
    • Research Site
  • Tel Hashomer, Israel, 52621
    • Research Site
• Mexico
  • Nuevo León
    • Monterrey, Nuevo León, Mexico, 64460
      • Research Site
• Poland
  • Bydgoszcz, Poland, 85-094
    • Research Site
  • Lodz, Poland, 91-738
    • Research Site
  • Olsztyn, Poland, 10-561
    • Research Site
  • Zabrze, Poland, 41-800
    • Research Site
• Russian Federation
  • Krasnodar, Russian Federation, 350007
    • Research Site
  • Moscow, Russian Federation, 117997
    • Research Site
  • Moscow, Russian Federation, 117198
    • Research Site
  • Saint-Petersburg, Russian Federation, 197022
    • Research Site
  • Saratov, Russian Federation, 410028
    • Research Site
  • Volgograd, Russian Federation, 400138
    • Research Site
• South Africa
  • Gauteng
    • Johannesburg, Gauteng, South Africa, 2013
      • Research Site
    • Parktown, Gauteng, South Africa, 2193
      • Research Site
  • KwaZulu-Natal
    • Durban, KwaZulu-Natal, South Africa, 4001
      • Research Site
  • Western Cape
    • Tygerberg, Western Cape, South Africa, 7505
      • Research Site
• Spain
  • Madrid, Spain, 28046
    • Research Site
  • Madrid, Spain, 28009
    • Research Site
  • Cataluña
    • Barcelona, Cataluña, Spain, 08035
      • Research Site
    • Esplugues de Llobregat, Cataluña, Spain, 08950
      • Research Site
  • Comunidad Valenciana
    • Valencia, Comunidad Valenciana, Spain, 46026
      • Research Site
• Switzerland
  • Basel, Switzerland, 4056
    • Research Site
  • St. Gallen, Switzerland, 9006
    • Research Site
  • Zuerich, Switzerland, 8032
    • Research Site
• Turkey
  • Adana, Turkey, 01130
    • Research Site
  • Antalya, Turkey, 07059
    • Research Site
  • Izmir, Turkey, 35100
    • Research Site
• United Kingdom
  • Birmingham, United Kingdom, B4 6NH
    • Research Site
  • Edinburgh, United Kingdom, EH9 1LF
    • Research Site
  • London, United Kingdom, W12 0HS
    • Research Site
  • Manchester, United Kingdom, M13 9WL
    • Research Site
• United States
  • California
    • Roseville, California, United States, 95661
      • 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
  • Missouri
    • Kansas City, Missouri, United States, 64108
      • Research Site
  • Nevada
    • Las Vegas, Nevada, United States, 89109
      • Research Site
  • New York
    • 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: 4 months to 16 years (Child, Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Diagnosis of primary ITP according to The American Society of Hematology (ASH) Guidelines at least 6 months before screening, regardless of splenectomy status
• Age ≥ 1 year and < 18 years of age
• Refractory to prior ITP therapy, relapsed after at prior ITP therapy, or be ineligible for other therapies. Examples of prior therapy include: corticosteroids, intravenous Immunoglobulin (IVIG), anti-D immunoglobulin, platelet transfusions.
• Platelet count ≤ 30 x10^9/L or is experiencing uncontrolled bleeding
• Has provided informed consent before any study-specific procedure;

• Adequate hematologic, renal, and liver function during screening:

  • Hemoglobin > 10.0 g/dL
  • Serum creatinine ≤ 1.5 x the upper limit of normal (ULN)
  • Total serum bilirubin ≤ 1.5 x the ULN
  • Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3.0 x the ULN
• For the EU, Switzerland and Turkey protocol supplement, subject must agree to a scheduled bone marrow biopsy and aspirate at Year 1 or Year 2 following romiplostim treatment and any unscheduled biopsies if clinically indicated
• For the EU, Switzerland and Turkey protocol supplement, a reticulin grade of 0, 1, 2, or 3 according to the modified Bauermeister grading scale, as assessed by central laboratory from a bone marrow biopsy performed within 1 year prior to planned first dose of romiplostim or consent to a pre-treatment bone marrow biopsy and aspirate prior to planned first dose of romiplostim

Exclusion Criteria:

• 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)
• Prior bone marrow transplant or peripheral blood progenitor cell transplant
• Active or prior malignancy except non-melanoma skin cancers within the last 5 years
• History of myelodysplastic syndrome
• History of bleeding diathesis
• History of congenital thrombocytopenia
• History of Hepatitis B, Hepatitis C or human immunodeficiency virus (HIV)
• History of systemic lupus erythematosus, Evans syndrome, or autoimmune neutropenia
• History of antiphospholipid antibody syndrome or known positive for lupus anticoagulant
• History of disseminated intravascular coagulation, hemolytic uremic syndrome, or thrombotic thrombocytopenic purpura
• History of venous thromboembolism or thrombotic events
• Previous use of romiplostim or previous use of eltrombopag within 4 weeks of enrollment
• Previous use of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), recombinant human thrombopoietin (rHuTPO) or any other platelet producing agent
• Rituximab (for any indication) or 6-mercaptopurine within 8 weeks of enrollment, or anticipated use at any time during the study
• Splenectomy within 4 weeks of 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
• Currently enrolled in another investigational device or drug study, or less than 30 days since ending investigational study
• Will have investigational procedures while enrolled on study
• Female subject of child bearing potential (defined as having first menses) not willing to use, in combination with her partner highly effective methods of birth control during treatment and for 1 month after the end of treatment
• Subject is pregnant or breast feeding, or might become pregnant within 1 month after the end of treatment
• Subject has known hypersensitivity to any recombinant Escherichia coli derived product (eg, Infergen®, Neupogen®, somatropin, and Actimmune®)
• Has previously enrolled into this study
• Will not be available for protocol-required study visits or procedures, to the best of the subject's and investigator's knowledge
• Any kind of disorder that, may compromise 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: 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; Participants received romiplostim administered weekly by subcutaneous injection for up to 3 years. The starting dose was 1 µg/kg titrated in 1 µg/kg increments up to a maximum of 10 µg/kg to reach a target platelet count ≥ 50 x 10⁹/L.	Drug: Romiplostim; Romiplostim subcutaneous weekly injection; Other Names: Nplate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Time With a Platelet Response During the First 6 Months of Treatment	Platelet response was defined as a platelet count of ≥ 50 x 10⁹/L with no rescue medication use for ITP in the past 4 weeks. Monthly platelet response was calculated based on the median platelet count during each month. For each participant, the percentage of time with platelet response during the first 6 months was calculated as the number of months a platelet response was observed divided by the total number of months response was assessed.	Week 2 to Month 6, platelet response was assessed every week.
Percentage of Participants Who Developed Collagen After Exposure to Romiplostim	The percentage of participants who developed collagen as evidenced by trichrome staining, defined as a Grade 4 on the modified Bauermeister grading scale: Grade 0: No reticulin fibers demonstrable Grade 1: Occasional fine individual fibers and foci of a fine fiber network Grade 2: Fine fiber network throughout most of the section; no coarse fibers Grade 3: Diffuse fiber network with scattered thick coarse fibers but no mature collagen (negative to trichrome staining) Grade 4: Diffuse, often course fiber network with areas of collagenization (positive trichrome staining)	Year 1 (Cohort 1) and year 2 (Cohort 2)
Percentage of Participants With Increased Modified Bauermeister Grade	The percentage of participants with an increased modified Bauermeister grade defined as an increase by ≥ 2 severity grades or an increase to grade 4 (i.e., grade 0 to 2-4, grade 1 to 3-4, grade 2 to 4, or grade 3 to 4 over baseline). The modified Bauermeister grading scale: Grade 0: No reticulin fibers demonstrable Grade 1: Occasional fine individual fibers and foci of a fine fiber network Grade 2: Fine fiber network throughout most of the section; no coarse fibers Grade 3: Diffuse fiber network with scattered thick coarse fibers but no mature collagen (negative to trichrome staining) Grade 4: Diffuse, often course fiber network with areas of collagenization (positive trichrome staining) Participants without an evaluable baseline result were assumed to have a baseline modified Bauermeister score of 0.	Baseline, year 1 (Cohort 1) and year 2 (Cohort 2)
Percentage of Participants Who Developed Bone Marrow Abnormalities	The percentage of participants with bone marrow abnormalities (eg, myelodysplastic syndrome, monosomy 7) based on analysis of bone marrow biopsy and aspirate samples using cytogenetics and fluorescence in situ hybridization.	Year 1 (Cohort 1) and year 2 (Cohort 2)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Time With a Platelet Response During the Overall Treatment Period	Platelet response was defined as a platelet count of ≥ 50 x 10⁹/L with no rescue medication use in the past 4 weeks. Monthly platelet response was calculated based on the median platelet count during each month. For each participant, the percentage of time with platelet response was calculated as the number of months a platelet response was observed divided by the total number of months response was assessed.	From week 2 to the end of the treatment period, 36 months
Percentage of Time With an Increase in Platelet Count ≥ 20 x 10⁹ Cells/L Above Baseline	The percentage of time with an increase in platelet count ≥ 20 x 10⁹ cells/L above baseline from week 2 until the end of the treatment period without rescue medication use within the past 4 weeks. For each participant, the percentage of time with an increase in platelet count ≥ 20 x10⁹ cells/L above baseline was calculated as the number of months the median platelet count was ≥ 20 x10⁹ cells/L above baseline divided by the total number of months assessed.	Baseline and from week 2 to month 36
Number of Participants Reporting Use of Rescue Medications for ITP During the Treatment Period	Rescue medication is defined as any medication or transfusion, other than romiplostim and excluded medications, that is administered after enrollment to the participant with the intent of raising platelet counts or to prevent bleeding and includes concomitant medications for ITP in which the dose and/or schedule was increased. Permitted rescue medications included the following: corticosteroids; platelet transfusions; Intravenous immunoglobulin (IVIG); azathioprine; anti-D immunoglobulin; danazol	From first dose of romiplostim to the end of the treatment period, 36 months
Number of Participants Who Developed Anti-Romiplostim or Anti-Thrombopoietin Neutralizing Antibodies	Blood samples were first tested for the presence of binding antibodies to romiplostim or the peptide portion of romiplostim, and to endogenous thrombopoietin (eTPO). Samples testing positive for binding antibodies were then tested for neutralizing antibodies by assessing their ability to neutralize romiplostim and/or eTPO in a cell-based bioassay. Participants who developed neutralizing antibodies are those who had a postbaseline positive result with a negative or no result at baseline. Transient is defined as a negative result at the participant's last time point tested within the study period.	Week 12, week 52 and every 24 weeks thereafter up to month 36
Number of Participants With Adverse Events	An adverse event (AE) was defined as any untoward medical occurrence in a clinical trial participant, which does not necessarily have a causal relationship with study treatment. A serious adverse event (SAE) was defined as an AE that met at least 1 of the following criteria: fatal; life threatening; 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 Adverse events were graded for severity according to 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; Grade 5 = death related to AE.	SAEs were collected from Screening through end-of-study follow-up (up to 38 months). Nonserious AEs were collected from first to last dose of study drug during the treatment period (up to 36 months).
Percentage of Participants Who Developed Increased Reticulin	The percentage of participants with increased reticulin as evidenced by silver staining and defined as any increase from baseline in the modified Bauermeister grade: Grade 0: No reticulin fibers demonstrable Grade 1: Occasional fine individual fibers and foci of a fine fiber network Grade 2: Fine fiber network throughout most of the section; no coarse fibers Grade 3: Diffuse fiber network with scattered thick coarse fibers but no mature collagen (negative to trichrome staining) Grade 4: Diffuse, often course fiber network with areas of collagenization (positive trichrome staining) Participants without an evaluable baseline result were assumed to have a baseline modified Bauermeister score of 0.	Baseline, year 1 (Cohort 1) and year 2 (Cohort 2)

Collaborators and Investigators

• Sponsor: Amgen

Publications and helpful links

General Publications

• Tarantino MD, Despotovic J, Roy J, Grainger J, Cooper N, Beam D, Raj A, Maschan A, Kim J, Eisen M. Romiplostim treatment for children with immune thrombocytopenia: Results of an integrated database of five clinical trials. Pediatr Blood Cancer. 2020 Nov;67(11):e28630. doi: 10.1002/pbc.28630. Epub 2020 Sep 9.
• Grainger J, Bussel JB, Tarantino MD, Cooper N, Beam D, Despotovic JM, Maschan A, Wang K, Eisen M, Bowers C. A Single-Arm, Long-Term Efficacy and Safety Study of Subcutaneous Romiplostim in Children with Immune Thrombocytopenia. Blood Adv. 2022 Apr 12:bloodadvances.2021006014. doi: 10.1182/bloodadvances.2021006014. Online ahead of print.

Helpful Links

• AmgenTrials clinical trials website

Study record dates

Study Major Dates

• Study Start (Actual): December 10, 2014
• Primary Completion (Actual): August 30, 2018
• Study Completion (Actual): August 8, 2019

Study Registration Dates

• First Submitted: October 1, 2014
• First Submitted That Met QC Criteria: October 29, 2014
• First Posted (Estimate): October 30, 2014

Study Record Updates

• Last Update Posted (Actual): June 23, 2022
• Last Update Submitted That Met QC Criteria: June 1, 2022
• Last Verified: June 1, 2022

More Information

Terms related to this study

• Keywords: Pediatric; Immune Thrombocytopenia; Amgen
• 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, Thrombocytopenic; Purpura; Purpura, Thrombocytopenic, Idiopathic; Thrombocytopenia
• Other Study ID Numbers: 20101221; 2011-005019-96 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: De-identified individual patient data for variables necessary to address the specific research question in an approved data sharing request
• IPD Sharing Time Frame: Data sharing requests relating to this study will be considered beginning 18 months after the study has ended and either 1) the product and indication (or other new use) have been granted marketing authorization in both the US and Europe or 2) clinical development for the product and/or indication discontinues and the data will not be submitted to regulatory authorities. There is no end date for eligibility to submit a data sharing request for this study.
• IPD Sharing Access Criteria: Qualified researchers may submit a request containing the research objectives, the Amgen product(s) and Amgen study/studies in scope, endpoints/outcomes of interest, statistical analysis plan, data requirements, publication plan, and qualifications of the researcher(s). In general, Amgen does not grant external requests for individual patient data for the purpose of re-evaluating safety and efficacy issues already addressed in the product labelling. Requests are reviewed by a committee of internal advisors, and if not approved, may be further arbitrated by a Data Sharing Independent Review Panel. Upon approval, information necessary to address the research question will be provided under the terms of a data sharing agreement. This may include anonymized individual patient data and/or available supporting documents, containing fragments of analysis code where provided in analysis specifications. Further details are available at the link below.
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP); Informed Consent Form (ICF); Clinical Study Report (CSR)