Study on Bone Marrow Morphology in Adults Receiving Romiplostim for Treatment of Thrombocytopenia Associated With Immune Thrombocytopenia Purpura (ITP)

Phase 4

Completed

• Conditions: Thrombocytopenia; Idiopathic Thrombocytopenic Purpura
• Interventions: Biological: romiplostim

• Registration Number: NCT00907478
• Lead Sponsor: Amgen

Brief Summary

The purpose of this study is to evaluate changes in bone marrow morphology (structure) after long-term exposure to romiplostim.

Detailed Description

Participants diagnosed with ITP according to the American Society of Hematology (ASH) Guidelines were sequentially enrolled into the following groups:

* Bone marrow biopsy at Baseline and Year 1

* Bone marrow biopsy at Baseline and Year 2

* Bone marrow biopsy at Baseline and Year 3.

All participants received romiplostim for 3 years, unless withdrawn from the study early. Participants returned for one visit for End of Study (EOS) procedures 4 weeks after romiplostim discontinuation, or, for participants who were withdrawn from the study due to the presence of collagen fibrosis, or had a change to grade 3 reticulin, at 12 weeks after discontinuation of romiplostim.

Study Timeline

• Study First Submitted: 2009-05-21
• Study First Submitted QC: 2009-05-21
• Study First Posted: 2009-05-22
• Study Start: 2009-08-11
• Primary Completion: 2014-01-09
• Study Completion: 2014-01-14
• Results First Submitted: 2014-12-19
• Results First Submitted QC: 2014-12-19
• Results First Posted: 2015-01-01
• Status Verified: 2022-09
• Last Update Submitted: 2022-09-08
• Last Update Posted: 2022-09-21

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 169

Inclusion Criteria

• Diagnosis of ITP according to American Society of Hematology (ASH) guidelines
• Subject must have had a bone marrow biopsy within one year prior to planned first dose of romiplostim (with available bone marrow tissue block or unstained histological slides to send to a central laboratory for interpretation) or must consent to a pre-treatment bone marrow biopsy within 3 weeks prior to planned first dose of romiplostim. Central laboratory interpretation is required prior to first dose of romiplostim
• Subject must agree to a scheduled bone marrow biopsy at Year 1, Year 2, or Year 3 following romiplostim treatment and any unscheduled biopsies if clinically indicated
• Subject ≥18 years of age
• Baseline bone marrow reticulin grade of 0, 1, 2, or 3 according to the modified Bauermeister grading scheme as assessed by central laboratory interpretation
• Platelet count < 50 x 10^9/L
• Must have received at least 1 prior ITP therapy (examples of ITP therapy include corticosteroids, intravenous immunoglobulin [IVIG], splenectomy)
• Subject (or legally-acceptable representative) is willing and able to provide written informed consent

Exclusion Criteria

• Baseline bone marrow biopsy positive for collagen fibrosis
• Any known history of or currently active bone marrow stem cell disorder, hematological malignancy, myeloproliferative disorder, myelodysplastic syndrome
• Any current active malignancy
• Any prior exposure to cytostatic chemotherapy or radiotherapy for malignancy
• Subject has undergone pacemaker placement, cardiac ablation of arrhythmia, and/or any current treatment with Vaughan Williams Class IA - IC and Class III agents (Vaughan Williams, 1970)
• Subject has participated in any study evaluating pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), recombinant human thrombopoietin (rHuTPO), or thrombopoietin receptor agonists (ie romiplostim or eltrombopag)
• Subject has a known hypersensitivity to any recombinant E coli-derived product
• Subject is currently enrolled in or has not yet completed (at least 4 weeks since ending) other investigational device or drug trial(s) or subject is receiving other investigational agent(s)
• Other investigational procedures are excluded
• Subject of child-bearing potential is evidently pregnant (eg positive pregnancy test) or is breast feeding
• Subject is not using adequate contraceptive precautions
• Subject has any kind of disorder that compromises the ability of the subject to give written informed consent and does not have a legally acceptable representative and/or is unable to comply with study procedures.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Romiplostim	romiplostim	Participants received romiplostim administered weekly by subcutaneous injection for up to 3 years. 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 ≥ 50 x 10\^9/L.

Primary Outcome Measures

Name	Time	Method
Percentage of Participants With Collagen Fibrosis	At Years 1, 2 or 3 after initial exposure of romiplostim	The percentage of participants who developed collagen fibrosis as evidenced by trichrome staining. Bone marrow biopsy samples were assessed using the modified Bauermeister grading scale by a central laboratory.

Secondary Outcome Measures

Name	Time	Method
Percentage of Participants Who Developed an Increased Modified Bauermeister Grade	At Year 1, Year 2, or Year 3 post romiplostim exposure	Increased modified Bauermeister grade refers to an increase by ≥ 2 severity grades or an increase to grade 4 (ie, grade 0 to 2-4, grade 1 to 3-4, grade 2 to 4, or grade 3 to 4 over baseline). The modified Bauermeister scale provides a means of assessing the development of increased reticulin and collagen in bone marrow according to the following: 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).
Number of Participants With Improvement of Reticulin to a Grade of ≤ 2 for Participants Who Developed Grade 3 Reticulin	12 weeks after romiplostim discontinuation	The number of participants who had any improvement of reticulin to a grade of ≤ 2 for participants who developed grade 3 reticulin after initial exposure to romiplostim as measured by the modified Bauermeister grading scale. The modified Bauermeister scale provides a means of assessing the development of increased reticulin and collagen in bone marrow according to the following: 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).
Number of Participants With Collagen Fibrosis 12 Weeks After Romiplostim Discontinuation in Participants Who Developed Collagen Fibrosis at Years 1, 2, or 3	12 weeks after romiplostim discontinuation	The number of participants with collagen fibrosis as evidenced by trichrome staining 12 weeks after romiplostim discontinuation in participants who developed collagen fibrosis at Years 1, 2, or 3 after initial exposure of romiplostim, assessed by the central laboratory using the modified Bauermeister grading scale.
Percentage of Participants With Clinically Relevant Changes in Total Cardiac Output Corrected (QTc) Intervals	Baseline, Week 3 and Week 12	A clinically relevant change in QTc (Fridericia) interval is defined as an absolute QTc interval \>500 ms or a QTc Interval increase from Baseline \>60 ms post romiplostim exposure. 12-lead electrocardiograms (ECG) were performed in triplicate at Baseline, Week 3 and Week 12; the average of of the 3 values at each assessment was used.
Number of Participants With Adverse Events (AEs)	From the first dose of study drug until 4 weeks after treatment discontinuation or 12 weeks after treatment discontinuation for patients who developed collagen fibrosis or a change to grade 3 reticulin; the overall median treatment duration was 154 weeks.	An AE was defined as any untoward medical occurrence in a participant that did not necessarily have a causal relationship with this treatment, or any such occurrence or worsening of a pre-existing medical condition from the first dose of investigational product through the last study visit. A serious adverse event is defined as an AE that is fatal or life threatening, requires or prolongs hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or other significant medical hazard. The relationship of each AE to the study drug was assessed by the investigator. The severity of each AE was graded using using CTCAE 3.0; For any AEs not listed in CTCAE, the Amgen Standard Severity Scoring System was used: 1: Mild- Aware of sign or symptom, but easily tolerated; 2 Moderate- Discomfort enough to cause interference with usual activity; 3: Severe- Incapacitating with inability to work or do usual activity; 4: Life-threatening; 5: Fatal.
Percentage of Participants With CTCAE Grade ≥ 2 Shift in Anemia or Neutropenia	From the first dose of study drug until 4 weeks after treatment discontinuation or 12 weeks after treatment discontinuation for patients who developed collagen fibrosis or a change to grade 3 reticulin; the overall median treatment duration was 154 weeks.	Anemia was identified by laboratory values with hemoglobin \< the lower limit of normal (LLN) or the Medical Dictionary for Regulatory Activities (MedDRA) terms prespecified by the sponsor. Neutropenia was identified by laboratory values with absolute neutrophil count \<1.8x10\^9/L or the MedDRA terms pre-specified by the sponsor. Severity was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0, based on the following: 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.
Number of Participants Who Developed Antibodies or Neutralizing Antibodies to Romiplostim or to Endogenous Thrombopoietin	Every 24 weeks and at the end of study visit (4 weeks or 12 weeks after study drug discontinuation).	Two validated assays were used to test for antibodies to romiplostim, the thrombopoietin-mimetic peptide component of romiplostim (TMP) and 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.; Persistent antibodies were those positive at the last timepoint tested and transient are defined as positive post-dose but negative at the last time point tested.