Idiopathic Thrombocytopenic Purpura
Conditions
Keywords
Immune Thrombocytopenic Purpura, Idiopathic Thrombocytopenic Purpura, Thrombocytopenic, Thrombocytopenia, ITP
Brief summary
The primary objective of this study is to evaluate the safety and tolerability of romiplostim in thrombocytopenic patients with ITP.
Interventions
DRUGRomiplostim
Administered by subcutaneous injection
DRUGPlacebo
Administered by subcutaneous injection
Sponsors
Amgen
Study design
Allocation
RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)
Intervention model description
Part A was a sequential cohort dose escalation study. Part B was a randomized, placebo-controlled parallel group study.
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Diagnosis of ITP according to American Society of Hematology (ASH) guidelines at least 3 months before enrollment * Have completed at least 1 prior treatment for ITP * Two (including day -2) of the 3 platelet counts taken during the screening and pre-treatment periods must have fulfilled the following: * less than 30 x 10\^9/L for those subjects not receiving any ITP therapy, * less than 50 x 10\^9/L for those subjects receiving any ITP therapy * Eastern Cooperative Oncology Group performance status of 0 to 2 * Serum creatinine concentration ≤ 2 mg/dL (≤ 176.8 µmol/L) * Adequate liver function, as evidenced by a serum bilirubin ≤ 1.5 times the laboratory normal range * Hemoglobin greater than 10.0 g/dL * Written informed consent
Exclusion criteria
* Considered a substantial risk for adverse outcomes because of a clinically important trend (as determined by the investigator) detected in the platelet counts during the screening period * Any known history of bone marrow stem cell disorder * Any active malignancy. If prior history of cancer other than basal cell carcinoma or cervical carcinoma in situ, no treatment or active disease within 5 years before randomization * Documented diagnosis of arterial thrombosis (ie, stroke, transient ischemic attack, or myocardial infarction) in the previous year; history of venous thrombosis (ie, deep vein thrombosis, pulmonary embolism) and receiving anticoagulation therapy * Unstable or uncontrolled disease or condition related to or impacting cardiac function (e.g., unstable angina, congestive heart failure \[New York Heart Association (NYHA) greater than class II\], uncontrolled hypertension \[diastolic greater than 100 mmHg\] or cardiac arrhythmia) * Have 3 or more of the following predisposing factors for thromboembolic events: diabetes; smoker using oral contraceptives; hypercholesteremia (\> 240 mg/dL); treatment for hypertension * Known positive test for human immunodeficiency virus (HIV) infection or hepatitis C virus * Received any treatment for ITP (except for a constant dose schedule of corticosteroids) within 4 weeks before the screening visit * Received intravenous (IV) immunoglobulin (Ig) or WinRho within 2 weeks before the screening visit * Received hematopoietic growth factors, including interleukin (IL)-11 (Neumega®) within 4 weeks before the screening visit * Past or present participation in any study evaluating polyethylene glycol recombinant human magakaryopoiesis differentiating factor (PEG-rHuMGDF), recombinant human thrombopoietin (rHuTPO), or related platelet product * Received any alkylating agents within 8 weeks before the screening visit or anticipated use during the time of the proposed study * Received any monoclonal antibody (eg, rituximab) within 16 weeks before the screening visit or anticipated use during the time of the proposed study * Less than 4 weeks since receipt of any therapeutic drug or device that is not FDA approved for any indication before the screening period * Less than 2 months since major surgery (including laparoscopic splenectomy) * Pregnant or breast feeding * Subjects of reproductive potential who are not using adequate contraceptive precautions, in the judgment of the investigator
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With Adverse Events | From first dose of study drug through 8 weeks (Part A) or 6 weeks (Part B) after last dose of study drug; 78 days | — |
| Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Assessed on day 29 (Part A only), day 43 (Part B only), and day 78 | The development of antibodies to romiplostim or to endogenous thrombopoietin (eTPO) was assessed using a neutralizing bioassay. Participants positive for neutralizing antibodies at any of the assessments during the study are reported. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78) | Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders. |
| Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78) | Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders. |
| Peak Platelet Count After Each Dose in Part A | After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78) | Platelet count data after the use of rescue medication were not included. |
| Change From Baseline in Peak Platelet Count After Each Dose in Part A | Baseline and after first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78) | Platelet count data after the use of rescue medication were not included. |
| Time to Peak Platelet Count After Each Dose in Part A | After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78) | Platelet count data after the use of rescue medication were not included. |
| Duration Within the Targeted Therapeutic Platelet Range In Part A | After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78) | Targeted therapeutic platelet level was defined as a platelet count that was double the baseline level and ≥ 50 and ≤ 450 × 10⁹ cells/L. Platelet count data after the use of rescue medication were not included. |
| Percentage of Participants Who Achieved Targeted Therapeutic Platelet Level In Part B | Day 1 to day 78 | Targeted therapeutic platelet level was defined as a doubling of baseline platelet counts and within the range of greater than or equal to 50 x 10⁹ cells/L and less than or equal to 450 x 10⁹ cells/L. Platelet count data after use of rescue medication were not included in the analysis. |
| Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78) | Targeted therapeutic platelet level was defined as a doubling of baseline platelet counts and between 50 to 450 x 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. |
| Percentage of Participants With a Peak Platelet Count of ≥ 100 x 10⁹ Cells/L in Part B | Day 1 to day 78 | Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders. |
| Percentage of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part B | Day 1 to day 78 | Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders. |
| Percentage of Participants With a Peak Platelet Count of > 500 x 10⁹ Cells/L in Part B | Day 1 to day 78 | Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders. |
| Peak Platelet Count in Part B | Day 1 to day 78 | Platelet count data after administration of rescue medication were not included in the analysis. |
| Change From Baseline in Peak Platelet Count in Part B | Baseline and day 1 to day 78 | Platelet count data after administration of rescue medication were not included in the analysis. |
| Time to Peak Platelet Count in Part B | Day 1 to day 78 | Platelet count data after administration of rescue medication were not included in the analysis. Time to peak platelet count was analyzed using the Kaplan-Meier method. |
| Duration Within the Targeted Therapeutic Platelet Range in Part B | Day 1 to day 78 | Targeted therapeutic platelet level was defined as a doubling of baseline platelet counts and within the range of greater than or equal to 50 × 10⁹ cells/L and less than or equal to 450 × 10⁹ cells/L. Platelet count data after administration of rescue medication were not included in the analysis. |
| Percentage of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part B | Day 1 to day 78 | Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders. |
| Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After first dose (day 1 to day 15 or 22), and after second dose (day 15 or 22 to day 78) | Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders. |
Participant flow
Recruitment details
This study consisted of 2 parts. Part A (conducted from July 1, 2002 to October 13, 2003) was an open-label, dose-escalation trial with sequential cohorts of participants. Part B (conducted from October 6, 2003 to June 17, 2004) was a double-blind, placebo-controlled, parallel design study.
Pre-assignment details
In Part A participants were sequentially assigned to escalating dose cohorts. In Part B, participants were randomized to each dose cohort; within each cohort 2 of 10 participants were randomly assigned to receive placebo. The 6.0 µg/kg dose cohort was discontinued in protocol amendment 4.
Participants by arm
| Arm | Count |
|---|---|
| Part A: Romiplostim 0.2 µg/kg Participants received 0.2 µg/kg romiplostim on day 1 and day 15 or 22, depending on platelet counts | 4 |
| Part A: Romiplostim 0.5 µg/kg Participants received 0.5 µg/kg romiplostim on day 1 and day 15 or 22, depending on platelet counts. | 4 |
| Part A: Romiplostim 1.0 µg/kg Participants received 1.0 µg/kg romiplostim on day 1 and on day 15 or 22 depending on platelet counts. | 4 |
| Part A: Romiplostim 3 µg/kg Participants received 3.0 µg/kg romiplostim on day 1 and day 15 or 22, depending on platelet counts. | 4 |
| Part A: Romiplostim 6 µg/kg Participants received 6.0 µg/kg romiplostim on day 1 and day 15 or 22, depending on platelet counts. | 4 |
| Part A: Romiplostim 10 µg/kg Participants received 10.0 µg/kg romiplostim on day 1 and day 15 or 22, depending on platelet counts. | 4 |
| Part B: Placebo Participants received placebo by subcutaneous injection once a week for 6 weeks. | 4 |
| Part B: Romiplostim 1.0 µg/kg Participants received 1.0 µg/kg romiplostim by subcutaneous injection once a week for 6 weeks. | 8 |
| Part B: Romiplostim 3.0 µg/kg Participants received 3.0 µg/kg romiplostim by subcutaneous injection once a week for 6 weeks. | 8 |
| Part B: Romiplostim 6.0 µg/kg Participants received 6.0 µg/kg romiplostim by subcutaneous injection once a week for 6 weeks. | 1 |
| Total | 45 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 | FG004 | FG005 | FG006 | FG007 | FG008 | FG009 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study | Lost to Follow-up | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
Baseline characteristics
| Characteristic | Part A: Romiplostim 3 µg/kg | Part A: Romiplostim 1.0 µg/kg | Part A: Romiplostim 0.5 µg/kg | Part A: Romiplostim 0.2 µg/kg | Total | Part A: Romiplostim 10 µg/kg | Part A: Romiplostim 6 µg/kg | Part B: Romiplostim 6.0 µg/kg | Part B: Romiplostim 3.0 µg/kg | Part B: Romiplostim 1.0 µg/kg | Part B: Placebo |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous Part A | 44.8 years STANDARD_DEVIATION 18.2 | 42.5 years STANDARD_DEVIATION 10.7 | 42.8 years STANDARD_DEVIATION 11.1 | 43.5 years STANDARD_DEVIATION 15 | 43.7 years STANDARD_DEVIATION 12.8 | 47.5 years STANDARD_DEVIATION 14.5 | 41.3 years STANDARD_DEVIATION 14.7 | — | — | — | — |
| Age, Continuous Part B | — | — | — | — | 14.3 years STANDARD_DEVIATION 49 | — | — | 42.0 years | 47.4 years STANDARD_DEVIATION 16.6 | 43.0 years STANDARD_DEVIATION 15 | 53.0 years STANDARD_DEVIATION 10.6 |
| Plateleet Count Part A | 13.4 1 × 10⁹ cells/L STANDARD_DEVIATION 6.81 | 9.06 1 × 10⁹ cells/L STANDARD_DEVIATION 4.19 | 14.5 1 × 10⁹ cells/L STANDARD_DEVIATION 12.5 | 10.7 1 × 10⁹ cells/L STANDARD_DEVIATION 2.7 | 13.1 1 × 10⁹ cells/L STANDARD_DEVIATION 7.93 | 18.4 1 × 10⁹ cells/L STANDARD_DEVIATION 10.1 | 12.6 1 × 10⁹ cells/L STANDARD_DEVIATION 9 | — | — | — | — |
| Plateleet Count Part B | — | — | — | — | 17.9 1 × 10⁹ cells/L STANDARD_DEVIATION 10.6 | — | — | 15.0 1 × 10⁹ cells/L | 14.0 1 × 10⁹ cells/L STANDARD_DEVIATION 6.2 | 16.9 1 × 10⁹ cells/L STANDARD_DEVIATION 7.86 | 28.4 1 × 10⁹ cells/L STANDARD_DEVIATION 17.7 |
| Race/Ethnicity, Customized Black | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 3 Participants | 1 Participants | 1 Participants | 0 Participants | 0 Participants | 1 Participants | 0 Participants |
| Race/Ethnicity, Customized Hispanic | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 6 Participants | 0 Participants | 0 Participants | 0 Participants | 3 Participants | 2 Participants | 1 Participants |
| Race/Ethnicity, Customized White | 4 Participants | 4 Participants | 4 Participants | 4 Participants | 36 Participants | 3 Participants | 3 Participants | 1 Participants | 5 Participants | 5 Participants | 3 Participants |
| Sex: Female, Male Female | 4 Participants | 4 Participants | 1 Participants | 3 Participants | 32 Participants | 2 Participants | 3 Participants | 1 Participants | 5 Participants | 6 Participants | 3 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 3 Participants | 1 Participants | 13 Participants | 2 Participants | 1 Participants | 0 Participants | 3 Participants | 2 Participants | 1 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk | EG004 affected / at risk | EG005 affected / at risk | EG006 affected / at risk | EG007 affected / at risk | EG008 affected / at risk | EG009 affected / at risk |
|---|---|---|---|---|---|---|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — | — / — | — / — | — / — | — / — | — / — | — / — | — / — |
| other Total, other adverse events | 4 / 4 | 4 / 4 | 4 / 4 | 4 / 4 | 4 / 4 | 4 / 4 | 4 / 4 | 8 / 8 | 8 / 8 | 1 / 1 |
| serious Total, serious adverse events | 2 / 4 | 0 / 4 | 0 / 4 | 0 / 4 | 0 / 4 | 1 / 4 | 2 / 4 | 0 / 8 | 1 / 8 | 0 / 1 |
Outcome results
Primary
Number of Participants With Adverse Events
Time frame: From first dose of study drug through 8 weeks (Part A) or 6 weeks (Part B) after last dose of study drug; 78 days
Population: All treated participants
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 2 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Adverse Events | Any adverse event | 4 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Adverse Events | Any adverse event | 4 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 3 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Any adverse event | 4 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Adverse Events | Any adverse event | 4 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Adverse Events | Any adverse event | 4 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Adverse Events | Any adverse event | 4 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 1 Participants |
| Part B: Placebo | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part B: Placebo | Number of Participants With Adverse Events | Any adverse event | 4 Participants |
| Part B: Placebo | Number of Participants With Adverse Events | Serious adverse events | 2 Participants |
| Part B: Placebo | Number of Participants With Adverse Events | Treatment-related adverse events | 1 Participants |
| Part B: Placebo | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part B: Placebo | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Any adverse event | 8 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 0 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 2 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 1 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 4 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 1 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Adverse Events | Any adverse event | 8 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Adverse Events | Any adverse event | 1 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Adverse Events | Treatment-related serious adverse events | 0 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Adverse Events | Treatment-related adverse events | 0 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Adverse Events | Serious adverse events | 0 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Adverse Events | Deaths | 0 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Adverse Events | Discontinuations due to adverse events | 0 Participants |
Primary
Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies
The development of antibodies to romiplostim or to endogenous thrombopoietin (eTPO) was assessed using a neutralizing bioassay. Participants positive for neutralizing antibodies at any of the assessments during the study are reported.
Time frame: Assessed on day 29 (Part A only), day 43 (Part B only), and day 78
Population: All treated participants
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part B: Placebo | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part B: Placebo | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part B: Romiplostim 1.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part B: Romiplostim 3.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-romiplostim neutralizing antibodies | 0 Participants |
| Part B: Romiplostim 6.0 µg/kg | Number of Participants With Anti-romiplostim or Anti-endogenous Thrombopoietin Neutralizing Antibodies | Anti-eTPO neutralizing antibodies | 0 Participants |
Secondary
Change From Baseline in Peak Platelet Count After Each Dose in Part A
Platelet count data after the use of rescue medication were not included.
Time frame: Baseline and after first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim and with a platelet count of ≥ 50 × 10⁹ cells/L and a doubling of the baseline platelet count, in the absence of rescue medication.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After first dose | 109.5 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 0.2 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After second dose | 51.50 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 3 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After second dose | 122.6 1 × 10⁹ cells/L | Standard Deviation 21.78 |
| Part A: Romiplostim 3 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After first dose | 150.2 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 6 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After first dose | 289.3 1 × 10⁹ cells/L | Standard Deviation 208.2 |
| Part A: Romiplostim 6 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After second dose | 220.0 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 10 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After first dose | 725.5 1 × 10⁹ cells/L | Standard Deviation 622.5 |
| Part A: Romiplostim 10 µg/kg | Change From Baseline in Peak Platelet Count After Each Dose in Part A | After second dose | 231.7 1 × 10⁹ cells/L | — |
Secondary
Change From Baseline in Peak Platelet Count in Part B
Platelet count data after administration of rescue medication were not included in the analysis.
Time frame: Baseline and day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Change From Baseline in Peak Platelet Count in Part B | 52.4 1 × 10⁹ cells/L | Standard Deviation 92.9 |
| Part A: Romiplostim 0.5 µg/kg | Change From Baseline in Peak Platelet Count in Part B | 117.6 1 × 10⁹ cells/L | Standard Deviation 88.3 |
| Part A: Romiplostim 1.0 µg/kg | Change From Baseline in Peak Platelet Count in Part B | 226.9 1 × 10⁹ cells/L | Standard Deviation 284.1 |
| Part A: Romiplostim 3 µg/kg | Change From Baseline in Peak Platelet Count in Part B | 505.0 1 × 10⁹ cells/L | — |
Secondary
Duration Within the Targeted Therapeutic Platelet Range In Part A
Targeted therapeutic platelet level was defined as a platelet count that was double the baseline level and ≥ 50 and ≤ 450 × 10⁹ cells/L. Platelet count data after the use of rescue medication were not included.
Time frame: After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim and with a platelet count ≥ 50 × 10⁹ cells/L and ≤ 450 × 10⁹ cells/L and a doubling of the baseline platelet count, in the absence of rescue medication.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After first dose | 5.0 days | — |
| Part A: Romiplostim 0.2 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After second dose | 3.0 days | — |
| Part A: Romiplostim 3 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After second dose | 3.5 days | Standard Deviation 2.1 |
| Part A: Romiplostim 3 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After first dose | 8.0 days | — |
| Part A: Romiplostim 6 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After first dose | 11.0 days | — |
| Part A: Romiplostim 6 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After second dose | 11.0 days | — |
| Part A: Romiplostim 10 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After first dose | 10.0 days | — |
| Part A: Romiplostim 10 µg/kg | Duration Within the Targeted Therapeutic Platelet Range In Part A | After second dose | 9.0 days | — |
Secondary
Duration Within the Targeted Therapeutic Platelet Range in Part B
Targeted therapeutic platelet level was defined as a doubling of baseline platelet counts and within the range of greater than or equal to 50 × 10⁹ cells/L and less than or equal to 450 × 10⁹ cells/L. Platelet count data after administration of rescue medication were not included in the analysis.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug and achieved a targeted therapeutic platelet level.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Duration Within the Targeted Therapeutic Platelet Range in Part B | 6.0 weeks |
| Part A: Romiplostim 0.5 µg/kg | Duration Within the Targeted Therapeutic Platelet Range in Part B | 3.0 weeks |
| Part A: Romiplostim 1.0 µg/kg | Duration Within the Targeted Therapeutic Platelet Range in Part B | 5.0 weeks |
| Part A: Romiplostim 3 µg/kg | Duration Within the Targeted Therapeutic Platelet Range in Part B | 4.0 weeks |
Secondary
Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A
Targeted therapeutic platelet level was defined as a doubling of baseline platelet counts and between 50 to 450 x 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.
Time frame: After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After second dose | 1 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After second dose | 2 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After second dose | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants Who Achieved Targeted Therapeutic Platelet Level in Part A | After second dose | 1 Participants |
Secondary
Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A
Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders.
Time frame: After first dose (day 1 to day 15 or 22), and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After second dose | 1 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After second dose | 3 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After first dose | 2 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After both doses | 2 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After second dose | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After first dose | 2 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After first dose | 3 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part A | After second dose | 1 Participants |
Secondary
Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A
Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders.
Time frame: After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After second dose | 2 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After both doses | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After first dose | 2 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After second dose | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After second dose | 1 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After first dose | 3 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With a Peak Platelet Count ≥ 100 x 10⁹ Cells/L in Part A | After both doses | 1 Participants |
Secondary
Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A
Platelet count data after the use of rescue medication were not included; participants with no platelet count data were considered non-responders.
Time frame: After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 0.2 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 0.5 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 1.0 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After first dose | 0 Participants |
| Part A: Romiplostim 3 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After first dose | 1 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
| Part A: Romiplostim 6 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After first dose | 2 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After both doses | 0 Participants |
| Part A: Romiplostim 10 µg/kg | Number of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part A | After second dose | 0 Participants |
Secondary
Peak Platelet Count After Each Dose in Part A
Platelet count data after the use of rescue medication were not included.
Time frame: After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim and with a platelet count of ≥ 50 × 10⁹ cells/L and a doubling of the baseline platelet count, in the absence of rescue medication.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Peak Platelet Count After Each Dose in Part A | After first dose | 123.0 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 0.2 µg/kg | Peak Platelet Count After Each Dose in Part A | After second dose | 65.0 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 3 µg/kg | Peak Platelet Count After Each Dose in Part A | After second dose | 140.5 1 × 10⁹ cells/L | Standard Deviation 29 |
| Part A: Romiplostim 3 µg/kg | Peak Platelet Count After Each Dose in Part A | After first dose | 163.0 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 6 µg/kg | Peak Platelet Count After Each Dose in Part A | After first dose | 309.0 1 × 10⁹ cells/L | Standard Deviation 202.2 |
| Part A: Romiplostim 6 µg/kg | Peak Platelet Count After Each Dose in Part A | After second dose | 244.0 1 × 10⁹ cells/L | — |
| Part A: Romiplostim 10 µg/kg | Peak Platelet Count After Each Dose in Part A | After first dose | 746.3 1 × 10⁹ cells/L | Standard Deviation 611.9 |
| Part A: Romiplostim 10 µg/kg | Peak Platelet Count After Each Dose in Part A | After second dose | 259.0 1 × 10⁹ cells/L | — |
Secondary
Peak Platelet Count in Part B
Platelet count data after administration of rescue medication were not included in the analysis.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Peak Platelet Count in Part B | 80.8 1 × 10⁹ cells/L | Standard Deviation 96 |
| Part A: Romiplostim 0.5 µg/kg | Peak Platelet Count in Part B | 134.5 1 × 10⁹ cells/L | Standard Deviation 90.2 |
| Part A: Romiplostim 1.0 µg/kg | Peak Platelet Count in Part B | 240.9 1 × 10⁹ cells/L | Standard Deviation 288.3 |
| Part A: Romiplostim 3 µg/kg | Peak Platelet Count in Part B | 520.0 1 × 10⁹ cells/L | — |
Secondary
Percentage of Participants Who Achieved Targeted Therapeutic Platelet Level In Part B
Targeted therapeutic platelet level was defined as a doubling of baseline platelet counts and within the range of greater than or equal to 50 x 10⁹ cells/L and less than or equal to 450 x 10⁹ cells/L. Platelet count data after use of rescue medication were not included in the analysis.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Percentage of Participants Who Achieved Targeted Therapeutic Platelet Level In Part B | 25 percentage of participants |
| Part A: Romiplostim 0.5 µg/kg | Percentage of Participants Who Achieved Targeted Therapeutic Platelet Level In Part B | 88 percentage of participants |
| Part A: Romiplostim 1.0 µg/kg | Percentage of Participants Who Achieved Targeted Therapeutic Platelet Level In Part B | 38 percentage of participants |
| Part A: Romiplostim 3 µg/kg | Percentage of Participants Who Achieved Targeted Therapeutic Platelet Level In Part B | 0 percentage of participants |
Secondary
Percentage of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part B
Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Percentage of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part B | 50 percentage of participants |
| Part A: Romiplostim 0.5 µg/kg | Percentage of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part B | 100 percentage of participants |
| Part A: Romiplostim 1.0 µg/kg | Percentage of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part B | 75 percentage of participants |
| Part A: Romiplostim 3 µg/kg | Percentage of Participants With an Increase in Platelet Count of ≥ 20 x 10⁹ Cells/L Over Baseline in Part B | 100 percentage of participants |
Secondary
Percentage of Participants With a Peak Platelet Count of ≥ 100 x 10⁹ Cells/L in Part B
Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Percentage of Participants With a Peak Platelet Count of ≥ 100 x 10⁹ Cells/L in Part B | 25 percentage of participants |
| Part A: Romiplostim 0.5 µg/kg | Percentage of Participants With a Peak Platelet Count of ≥ 100 x 10⁹ Cells/L in Part B | 63 percentage of participants |
| Part A: Romiplostim 1.0 µg/kg | Percentage of Participants With a Peak Platelet Count of ≥ 100 x 10⁹ Cells/L in Part B | 63 percentage of participants |
| Part A: Romiplostim 3 µg/kg | Percentage of Participants With a Peak Platelet Count of ≥ 100 x 10⁹ Cells/L in Part B | 100 percentage of participants |
Secondary
Percentage of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part B
Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Percentage of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part B | 0 percentage of participants |
| Part A: Romiplostim 0.5 µg/kg | Percentage of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part B | 0 percentage of participants |
| Part A: Romiplostim 1.0 µg/kg | Percentage of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part B | 25 percentage of participants |
| Part A: Romiplostim 3 µg/kg | Percentage of Participants With a Peak Platelet Count of > 450 x 10⁹ Cells/L in Part B | 100 percentage of participants |
Secondary
Percentage of Participants With a Peak Platelet Count of > 500 x 10⁹ Cells/L in Part B
Platelet count data after administration of rescue medication were not included in the analysis. Participants with no platelet count data were considered non-responders.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Percentage of Participants With a Peak Platelet Count of > 500 x 10⁹ Cells/L in Part B | 0 percentage of participants |
| Part A: Romiplostim 0.5 µg/kg | Percentage of Participants With a Peak Platelet Count of > 500 x 10⁹ Cells/L in Part B | 0 percentage of participants |
| Part A: Romiplostim 1.0 µg/kg | Percentage of Participants With a Peak Platelet Count of > 500 x 10⁹ Cells/L in Part B | 25 percentage of participants |
| Part A: Romiplostim 3 µg/kg | Percentage of Participants With a Peak Platelet Count of > 500 x 10⁹ Cells/L in Part B | 100 percentage of participants |
Secondary
Time to Peak Platelet Count After Each Dose in Part A
Platelet count data after the use of rescue medication were not included.
Time frame: After first dose (day 1 to day 15 or 22) and after second dose (day 15 or 22 to day 78)
Population: Participants enrolled in Part A who received each dose of romiplostim and with a platelet count of ≥ 50 × 10⁹ cells/L and a doubling of the baseline platelet count, in the absence of rescue medication.
| Arm | Measure | Group | Value (MEDIAN) |
|---|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After first dose | 10.0 days |
| Part A: Romiplostim 0.2 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After second dose | 10.0 days |
| Part A: Romiplostim 3 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After second dose | 11.0 days |
| Part A: Romiplostim 3 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After first dose | 11.0 days |
| Part A: Romiplostim 6 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After first dose | 9.5 days |
| Part A: Romiplostim 6 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After second dose | 10.0 days |
| Part A: Romiplostim 10 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After first dose | 15.0 days |
| Part A: Romiplostim 10 µg/kg | Time to Peak Platelet Count After Each Dose in Part A | After second dose | 11.0 days |
Secondary
Time to Peak Platelet Count in Part B
Platelet count data after administration of rescue medication were not included in the analysis. Time to peak platelet count was analyzed using the Kaplan-Meier method.
Time frame: Day 1 to day 78
Population: Participants randomized in Part B who received at least 1 dose of study drug.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Part A: Romiplostim 0.2 µg/kg | Time to Peak Platelet Count in Part B | 63 days |
| Part A: Romiplostim 0.5 µg/kg | Time to Peak Platelet Count in Part B | 18 days |
| Part A: Romiplostim 1.0 µg/kg | Time to Peak Platelet Count in Part B | 19 days |
| Part A: Romiplostim 3 µg/kg | Time to Peak Platelet Count in Part B | 21 days |