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Completed

NCT Number: NCT00117143

Amgen Megakaryopoiesis Protein 2 (AMG 531) in Thrombocytopenic Subjects With Immune Thrombocytopenic Purpura (ITP)

The purpose of this study is to assess the safety and tolerability of AMG 531 (romiplostim), a novel thrombopoiesis-stimulating peptibody, and its effect on platelet counts in adults with immune thrombocytopenic purpura.

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Key information

Conditions

Thrombocytopenic Purpura Autoimmune Diseases Blood Coagulation Disorders Blood Platelet Disorders Cytopenia Hematologic Diseases Hemic and Lymphatic Diseases Hemorrhage Hemorrhagic Disorders Immune System Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Purpura Purpura, Thrombocytopenic Purpura, Thrombocytopenic, Idiopathic Signs and Symptoms Skin Manifestations Thrombocytopenia Thrombotic Microangiopathies

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1 / Phase 2

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Greater than or equal to 3 months history of ITP, regardless of splenectomy status, and completion of at least 1 prior treatment for ITP
  • 2 of 3 pretreatment platelet counts that were less than 30 x 10^9/L (if not currently on ITP therapy) or less than 50 x 10^9/L (if currently receiving corticosteroids for ITP therapy)
  • Ability to give informed consent

Exclusion criteria

  • Known history of arterial thrombosis, active malignancy, or bone marrow stem cell disorder

Treatment and study plan

Romiplostim

Drug

Administered subcutaneously on day 1 and on day 15 or 22 if the platelet count was ≤ 50 x 10⁹/L and not rising, peak platelet count was ≤ 450 x 10⁹/L and no serious adverse events related to treatment were observed.

Other names: AMG 531, NPLATE

Primary outcomes

  1. Number of Participants With Adverse Events

    Time frame: From first dose through 8 weeks after last dose of study drug (11 weeks)

  2. Number of Participants With Positive Anti-Romiplostim Antibodies

    Time frame: Days 29 and 78

    The presence or development of antibodies to romiplostim and endogenous thrombopoietin was assessed using a neutralizing bioassay. Antibody analyses were conducted on study days 29 and at the end-of-study visit (day 78). The number of participants with positive antibody binding at any time during the study is reported.

Secondary outcomes

  1. Number of Participants Who Achieved a Targeted Therapeutic Platelet Response

    Time frame: Baseline and after first dose (days 3, 5, 8, 10, 12, 15, and days 17 and 19 for participants dosed on day 22) and after second dose (days 17, 19, and 22 for participants dosed on day 15, and days 24, 26, 29, 32, 36, 43, 50, 64, and 78 in all participants)

    Targeted therapeutic platelet response was defined as a (single) platelet count that was double the baseline level and between 50 and 450 × 10⁹ cells/L.

    Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders.

  2. Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L From Baseline

    Time frame: Baseline and after first dose (days 3, 5, 8, 10, 12, 15, and days 17 and 19 for participants dosed on day 22) and after second dose (days 17, 19, and 22 for participants dosed on day 15, and days 24, 26, 29, 32, 36, 43, 50, 64, and 78 in all participants)

    Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders.

  3. Number of Participants With Peak Platelet Counts of ≥ 100 x 10⁹ Cells/L

    Time frame: After first dose (days 3, 5, 8, 10, 12, 15, and days 17 and 19 for participants dosed on day 22), and after second dose (days 17, 19, and 22 for participants dosed on day 15, and days 24, 26, 29, 32, 36, 43, 50, 64, and 78 for all participants)

    Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders.

  4. Number of Participants With Peak Platelet Counts of ≥ 450 x 10⁹ Cells/L

    Time frame: After first dose (days 3, 5, 8, 10, 12, 15, and days 17 and 19 for participants dosed on day 22), and after second dose (days 17, 19, and 22 for participants dosed on day 15, and days 24, 26, 29, 32, 36, 43, 50, 64, and 78 for all participants)

    Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders.

  5. Change From Baseline to Peak Platelet Level

    Time frame: Baseline and after first dose (days 3, 5, 8, 10, 12, 15, and days 17 and 19 for participants dosed on day 22) and after second dose (days 17, 19, and 22 for participants dosed on day 15, and days 24, 26, 29, 32, 36, 43, 50, 64, and 78 in all participants)

    Platelet count data after the use of rescue medication were not included.

  6. Time to Peak Platelet Count

    Time frame: From first dose of study drug to day 15 or 22, and from the second dose of study drug (day 15 or 22) to day 78

    Time from the date of study drug administration (day 1, 15 or 22) to the day of peak platelet count after each dose. Platelet count data after the use of rescue medication were not included.

  7. Duration Within the Targeted Therapeutic Range

    Time frame: From first dose of study drug to day 15 or 22, and from the second dose of study drug (day 15 or 22) to day 78

    Targeted therapeutic platelet level was defined as a platelet count that was double the baseline level and between 50 and 450 × 10⁹ cells/L.

    Platelet count data after the use of rescue medication were not included.

Sponsors and collaborators

Lead sponsor

Amgen

Industry

Registry information

Official study title

An Open-label, Unit Dose-finding Study Evaluating the Safety and Efficacy of Amgen Megakaryopoiesis Protein 2 (AMG 531) in Thrombocytopenic Subjects With Immune Thrombocytopenic Purpura (ITP)

Important dates

Study start
2002
Primary completion
2004
Study completion
2004
First posted
Jul 4, 2005
Registry last updated
Jun 26, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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