Safety and Efficacy Study of Romiplostim to Treat Immune Thrombocytopenia (ITP) in Pediatric Patients
Condition: Idiopathic Thrombocytopenic Purpura; Thrombocytopenia; Thrombocytopenia in Pediatric Subjects With Immune (Idiopathic) Thrombocytopenic Purpura (ITP); Thrombocytopenia in Subjects With Immune (Idiopathic) Thrombocytopenic Purpura (ITP); Thrombocytopenic Purpura; Immune Thrombocytopenia
MeSH terms: Thrombocytopenia; Purpura; Purpura, Thrombocytopenic, Idiopathic; Purpura, Thrombocytopenic
Intervention: Romiplostim; Placebo
Intervention description: 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.; Matching placebo administered by subcutaneous injection
Phase: Phase 3
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Enrollment: 62.0
Sex: All
Minimum age: 1 Year
Maximum age: 17 Years
Healthy volunteers: No
Keywords: Immune (Idiopathic) Thrombocytopenic Purpura; Pediatric Immune (Idiopathic) Thrombocytopenic Purpura; Immune Thrombocytopenia

Summary:

      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.
    

Eligibility criteria:

        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