Chronic Thrombocytopenia, Immune Thrombocytopenia
Conditions
Keywords
Chronic Immune Thrombocytopenia
Brief summary
Core Study: To demonstrate that the efficacy of avatrombopag (in addition to standard of care) is superior to placebo (in addition to standard of care) for the treatment of adult participants with chronic immune thrombocytopenia (idiopathic thrombocytopenic purpura) (ITP) as measured by cumulative number of weeks of platelet response over 6 months of once daily treatment in adults participants who received at least 1 prior ITP therapy. Extension Phase: To evaluate the safety and tolerability of long-term therapy with avatrombopag in participants with chronic ITP (cITP).
Detailed description
This study consists three phases: Prerandomization, Randomization (Core Study) and Extension study. The overall duration of treatment (Core and Extension) is approximately 104 weeks with the Core study being 26 weeks and the Extension study being 76 weeks. Approximately 45 participants 18 years of age and over who meet all the eligibility requirements will be randomized. No single platelet count should be greater than 35x10\^9/L (liter). Participants will be centrally stratified at randomization by splenectomy status, baseline platelet count, and use of concomitant ITP medication at baseline, and randomized to receive either double-blind avatrombopag or placebo in a 2:1 ratio. Participants will receive blinded therapy at a starting dose of 20 mg avatrombopag or placebo once daily. Participants will be allowed to have their dose titrated up (maximum dose 40 mg avatrombopag or matching placebo) or down (minimum dose 5 mg for avatrombopag or matching placebo) depending on their response to study drug. The goal of dose modification is to maintain the platelet count at levels greater than or equal to 50x10\^9/L and less than or equal to 150x10\^9/L, and to decrease the need for ITP-directed concomitant medications.
Interventions
DRUGAvatrombopag
DRUGPlacebo
DRUGStandard of care
Permitted ITP concomitant background therapies are as follows: * Corticosteroids and/or azathioprine taken at a stable dose for 4 weeks before randomization; * Mycophenolate mofetil (MMF) or danazol taken at a stable dose for at least 12 weeks before randomization; * Cyclosporine A (CsA) (due to the fact that it is a P-glycoprotein-mediated transport \[P-gp\] inhibitor) is to be avoided unless deemed medically necessary; CsA taken at a stable dose for at least 12 weeks before randomization. At the discretion of the investigator, participants will be allowed to use aspirin, other salicylates, or approved adenosine diphosphate (ADP) receptor antagonists, (eg, clopidogrel, prasugrel) during the study once their platelet count had risen. Participants treated with proton pump inhibitors (PPIs) and H2 antagonist therapy will receive a stable dose for at least 6 weeks prior to randomization. Treatment with these therapies must have been completed at least 2 weeks prior to randomization.
Sponsors
Eisai Inc.
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Men and women greater than or equal to 18 years of age 2. Participants diagnosed with cITP (greater than or equal to 12 months duration) according to the American Society for Hematology/British Committee for Standards in Hematology (ASH/BCSH) guidelines, and an average of 2 platelet counts greater than 30x10\^9/L). The physical exam should not suggest any disease which may cause thrombocytopenia other than ITP 3. Participants who previously received one or more ITP therapies (including, but not limited to corticosteroids, immunoglobulins, azathioprine, danazol, cyclophosphamide and/or rituximab). 4. Participants must have had either initially responded (platelet count greater than 50x10\^9/L) to a previous ITP therapy or have had a bone marrow examination consistent with ITP within 3 years to rule out myelodysplastic syndrome (MDS) or other causes of thrombocytopenia 5. Prothrombin time/International Normalized Ratio (PT/INR) and activated partial thromboplastin time (aPTT) must have been within 80% to 120% of the normal range with no history of hypercoagulable state 6. A complete blood count within the reference range (including white blood count \[WBC\] differential not indicative of a disorder other than ITP), with the following exceptions: hemoglobin: participants with hemoglobin levels between 10 g/dL (100 g/L) and the lower limit of normal (LLN) are eligible for inclusion, if anemia was clearly attributable to ITP (excessive blood loss); Absolute neutrophil count (ANC) greater than or equal to 1500/uL (1.5x10\^9/L) (elevated WBC/ANC due to corticosteroid treatment is acceptable)
Exclusion criteria
1. Participants with known secondary immune thrombocytopenia (e.g., with known Helicobacter pylori-induced ITP participants infected with known human immunodeficiency virus \[HIV\] or hepatitis C virus \[HCV\] or participants with known systemic lupus erythematosus). (Revised per Amendment 01) 2. Participants with significant medical conditions that may impact on the safety of the participant or interpretation of the study results (e.g., acute hepatitis, active chronic hepatitis; lymphoproliferative disease; myeloproliferative disorders, leukemia) 3. History of MDS 4. History of gastric atrophy (added per Amendment 01) 5. History of pernicious anemia or participants with vitamin B12 deficiency (defined as less than LLN) who have not had pernicious anemia excluded as a cause (added per Amendment 01) 6. Any prior history of arterial or venous thrombosis (stroke, transient ischemic attack, myocardial infarction, deep vein thrombosis or pulmonary embolism), and more than two of the following risk factors: hormone replacement therapy, estrogen-containing hormone replacement or contraceptive therapies, smoking, diabetes, hypercholesterolemia, medication for hypertension, cancer, hereditary thrombophilic disorders (e.g., Factor V Leiden, antithrombin III deficiency, etc.), or any other family history of arterial or venous thrombosis 7. Participants with a history of significant cardiovascular disease (e.g., congestive heart failure \[CHF\] New York Heart Association Grade III/IV, arrhythmia known to increase the risk of thromboembolic events \[e.g., atrial fibrillation\], participants with a QT interval corrected for heart rate of \>450 msec, angina, coronary artery stent placement, angioplasty, coronary artery bypass grafting) 8. Participants with a history of cirrhosis, portal hypertension, and chronic active hepatitis 9. Participants with concurrent malignant disease 10. Use of immunoglobulins (IVIg and anti-D) within 1 week of randomization 11. Splenectomy or use of rituximab within 12 weeks of randomization 12. Use of romiplostim or eltrombopag within 4 weeks of randomization 13. Participants who are currently treated with corticosteroids or azathioprine but have not been receiving a stable dose for at least 4 weeks prior to randomization or have not completed these therapies more than 4 weeks prior to randomization 14. Participants who are currently treated with MMF, CsA, or danazol but have not been receiving a stable dose for at least 12 weeks prior to randomization or have not completed these therapies more than 4 weeks prior to randomization 15. Use of cyclophosphamide or vinca alkaloid regimens within 4 weeks of randomization 16. Participants who are currently treated with PPIs or H2 antagonist therapy but have not been receiving a stable dose for at least 6 weeks prior to randomization or have not completed these therapies more than 2 weeks prior to randomization 17. Fasting gastrin-17 blood levels exceeding the ULN at Screening for participants not on PPIs or H2 antagonists (Revised per Amendment 01) 18. Fasting gastrin-17 blood levels exceeding 1.5 times the upper limit of normal (ULN) at Screening for participants on PPIs or H2 antagonists (Added per Amendment 01) 19. Blood creatinine exceeding ULN by more than 20% OR total albumin below the lower limit of normal (LLN) by 10% 20. Alanine aminotransferase (ALT) OR aspartate aminotransferase (AST) levels exceeding 3 times the ULN or total bilirubin exceeding 2 times the ULN 21. Participants with a history of cancer treatment with cytotoxic chemotherapy and/or radiotherapy. 22. Participants with a history of ITP treatment with cytotoxic chemotherapy are still eligible for enrollment. 23. Females who are pregnant (positive beta-human chorionic gonadotropin positive \[B-hCG\] test) or breastfeeding 24. Participants with a known allergy to avatrombopag (E5501) or its excipients
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of Weeks With Platelet Count Greater Than or Equal to 50 x 10^9/L During 6-Month Treatment Period | Week 1 to Week 26 | The cumulative number of weeks of platelet response is defined as the total numbers of weeks in which the platelet count is greater than or equal to 50 x 10\^ 9/L during 6 months of treatment of core study in the absence of rescue therapy. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With a Reduction in Use of Concomitant Immune/Idiopathic Thrombocytopenic Purpura (ITP) Medication | Week 1 through Week 26 | Only participants on concomitant ITP medications at baseline were included. |
| Number of Participants With Platelet Count Greater Than or Equal to 50 x 10^9/L at Day 8 | Week 1 (Day 8) | Participants with platelet response at Day 8 are defined as those who had a platelet count greater than or equal to 50 x 10\^9/L at day 8 in the absence of rescue therapy on or before Day 8. |
Countries
Australia, Belgium, Bulgaria, Czechia, Netherlands, New Zealand, Poland, Singapore, Slovakia, South Africa, Ukraine
Participant flow
Pre-assignment details
A total of 100 participants were screened in study. Of these 100 participants, 51 were screen failures and 49 were randomized into the study.
Participants by arm
| Arm | Count |
|---|---|
| Placebo (Core Study) Placebo was administered as 5 mg, 10 mg, 20 mg, 30 mg or 40 mg in a flexible dose design for 26 weeks. Placebo was administered orally at a starting dose of 20 mg, once daily. Afterwards the dose could be titrated up (maximum dose of 40 mg avatrombopag) or down (minimum dose of 5 mg avatrombopag) depending on the participant's response to the study drug; placebo titration was used to maintain the blind. | 17 |
| Avatrombopag (Core Study) Avatrombopag was administered orally as 5 mg, 10 mg, 20 mg, 30 mg, or 40 mg in a flexible dose design for 26 weeks. Participants received blinded therapy at a starting dose of 20 mg avatrombopag, one daily and they were allowed to have their dose titrated up (maximum dose of 40 mg avatrombopag) or down (minimum dose of 5 mg avatrombopag) depending on their response to study drug. | 32 |
| Total | 49 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 |
|---|---|---|---|---|
| Core Study | Adverse Event | 0 | 3 | 0 |
| Core Study | Lack of Efficacy | 15 | 7 | 0 |
| Core Study | Withdrawal of consent | 1 | 0 | 0 |
| Extension Phase | Adverse Event | 0 | 0 | 3 |
| Extension Phase | Lack of Efficacy | 0 | 0 | 2 |
| Extension Phase | Lost to Follow-up | 0 | 0 | 1 |
| Extension Phase | Other | 0 | 0 | 1 |
| Extension Phase | Withdrawal by Subject | 0 | 0 | 3 |
Baseline characteristics
| Characteristic | Placebo (Core Study) | Avatrombopag (Core Study) | Total |
|---|---|---|---|
| Age, Continuous | 41.2 Years STANDARD_DEVIATION 14.7 | 46.4 Years STANDARD_DEVIATION 14.2 | 44.6 Years STANDARD_DEVIATION 14.44 |
| Sex: Female, Male Female | 8 Participants | 23 Participants | 31 Participants |
| Sex: Female, Male Male | 9 Participants | 9 Participants | 18 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — |
| other Total, other adverse events | 10 / 17 | 31 / 32 | 45 / 47 |
| serious Total, serious adverse events | 1 / 17 | 9 / 32 | 15 / 47 |
Outcome results
Primary
Number of Weeks With Platelet Count Greater Than or Equal to 50 x 10^9/L During 6-Month Treatment Period
The cumulative number of weeks of platelet response is defined as the total numbers of weeks in which the platelet count is greater than or equal to 50 x 10\^ 9/L during 6 months of treatment of core study in the absence of rescue therapy.
Time frame: Week 1 to Week 26
Population: Full Analysis Set (Core Study): All participants who were randomized into the study.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Placebo (Core Study) | Number of Weeks With Platelet Count Greater Than or Equal to 50 x 10^9/L During 6-Month Treatment Period | 0 Weeks |
| Avatrombopag (Core Study) | Number of Weeks With Platelet Count Greater Than or Equal to 50 x 10^9/L During 6-Month Treatment Period | 12.4 Weeks |
p-value: <0.0001Wilcoxon (Mann-Whitney)
Secondary
Number of Participants With a Reduction in Use of Concomitant Immune/Idiopathic Thrombocytopenic Purpura (ITP) Medication
Only participants on concomitant ITP medications at baseline were included.
Time frame: Week 1 through Week 26
Population: Full Analysis Set (Core Study): All participants who were randomized into the study.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Placebo (Core Study) | Number of Participants With a Reduction in Use of Concomitant Immune/Idiopathic Thrombocytopenic Purpura (ITP) Medication | Yes | 0 Participants |
| Placebo (Core Study) | Number of Participants With a Reduction in Use of Concomitant Immune/Idiopathic Thrombocytopenic Purpura (ITP) Medication | No | 7 Participants |
| Avatrombopag (Core Study) | Number of Participants With a Reduction in Use of Concomitant Immune/Idiopathic Thrombocytopenic Purpura (ITP) Medication | Yes | 5 Participants |
| Avatrombopag (Core Study) | Number of Participants With a Reduction in Use of Concomitant Immune/Idiopathic Thrombocytopenic Purpura (ITP) Medication | No | 10 Participants |
Secondary
Number of Participants With Platelet Count Greater Than or Equal to 50 x 10^9/L at Day 8
Participants with platelet response at Day 8 are defined as those who had a platelet count greater than or equal to 50 x 10\^9/L at day 8 in the absence of rescue therapy on or before Day 8.
Time frame: Week 1 (Day 8)
Population: Full Analysis Set (Core Study): All participants who were randomized into the study.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Placebo (Core Study) | Number of Participants With Platelet Count Greater Than or Equal to 50 x 10^9/L at Day 8 | No | 17 Participants |
| Placebo (Core Study) | Number of Participants With Platelet Count Greater Than or Equal to 50 x 10^9/L at Day 8 | Yes | 0 Participants |
| Avatrombopag (Core Study) | Number of Participants With Platelet Count Greater Than or Equal to 50 x 10^9/L at Day 8 | Yes | 21 Participants |
| Avatrombopag (Core Study) | Number of Participants With Platelet Count Greater Than or Equal to 50 x 10^9/L at Day 8 | No | 11 Participants |