STUDY DESIGN & BASELINE CHARACTERISTICS
A Phase 4, Open-Label, Multicenter Trial Evaluating Changes in BM Morphology1
A phase 4, open-label, multicenter trial prospectively evaluated bone marrow for reticulin formation and collagen
fibrosis in adult patients with immune thrombocytopenia (ITP) receiving Nplate® (romiplostim) or a
non-US-approved romiplostim product. A modified Bauermeister grading scale was used for both assessments.1
Modified Bauermeister scale: quantification of bone marrow reticulin and collagen9
GRADE 0 |
No reticulin |
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
trichrome staining) |
GRADE 4 |
Diffuse, coarse fiber network with areas of collagenization (positive trichrome staining)
|
Patients were administered Nplate® by subcutaneous injection once weekly for up to 3 years. Based on
cohort assignment at the time of study enrollment, patients were evaluated for bone marrow reticulin and
collagen at year 1 (cohort 1), year 2 (cohort 2), or year 3 (cohort 3) in comparison to the baseline
bone marrow at the start of the study. A total of 169 patients were enrolled in the 3
cohorts.1
Baseline characteristics9
- Mean age of 50 years
- Median baseline platelet count was 23 x 109/L (range, 0.5–130 x 109/L)
- 36% (60/169) of patients were splenectomized before enrollment
Study limitations9
- Lack of within-patient comparison over time
- Study design was chosen to limit patient discontinuation due to repeated bone biopsies