Immune ThrombocytopeniaPhase 3NCT05369208
Evaluation of Avatrombopag for the Treatment of Thrombocytopenia in Japanese Adults With Chronic ITP
A Phase 3 study testing Avatrombopag Oral Tablet in people with Immune Thrombocytopenia, run by Sobi, Inc. at 19 sites in Japan.
Trial summary
Evaluate the efficacy, safety, and PK of avatrombopag given for 26 weeks in Japanese adults with chronic immune thrombocytopenia (ITP). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Immune Thrombocytopenia
- What is being tested?
- Avatrombopag Oral Tablet
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 19 participants
- Where
- 19 sitesJapan
- Study dates
- 15 Jun 2022to 29 Oct 2025
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Subject has a confirmed diagnosis of chronic immune thrombocytopenia (ITP) (≥12 months duration) and has had an insufficient response to a previous ITP treatment, in the opinion of the Investigator.
- Subject has an average of 2 platelet counts <30×10^9/L (no single count can be >35×10^9/L). The 2 samples must be obtained ≥48 hours and ≤2 weeks apart.
Who cannot join
- Subjects with known secondary immune thrombocytopenia (e.g., with known Helicobacter pylori-induced ITP, subjects infected with known human immunodeficiency virus (HIV) or hepatitis C virus (HCV) or subjects with known systemic lupus erythematosus).
- Subjects with known inherited thrombocytopenia (e.g., Myosin Heavy Chain 9 (MYH-9) disorders) or hereditary thrombophilic disorders (e.g., Factor V Leiden, antithrombin III deficiency).
- History of myelodysplastic syndrome (MDS).
- History of arterial or venous thrombosis.
- Subjects 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], angina, coronary artery stent placement, angioplasty, coronary artery bypass grafting).
- Subjects with a history of cirrhosis, portal hypertension, or chronic active hepatitis.
Show all 19Show fewer
- Subjects with concurrent malignant disease or receiving cytotoxic chemotherapy for a reason other than ITP treatment.
- Use of immunoglobulins (IVIg and anti-D) or corticosteroid rescue therapy within 1 week of Day 1/Baseline.
- Splenectomy or use of rituximab within 12 weeks of Day 1/Baseline.
- Use of romiplostim or eltrombopag within 1 week of Day 1/Baseline.
- Use of chronic corticosteroid treatment or azathioprine within 4 weeks of Day 1/Baseline, unless receiving a stable dose for at least 4 weeks.
- Use of mycophenolate mofetil, cyclosporin A, or danazol within 4 weeks of Day 1/Baseline, unless receiving a stable dose for at least 12 weeks.
- Use of cyclophosphamide or vinca alkaloid regimens within 4 weeks of Baseline Visit.
- Currently receiving moderate or strong dual inhibitors/inducers of CYP2C9 and CYP3A4.
- Serum creatinine ≥1.5× the upper limit of normal (ULN).
- Serum bilirubin ≥2×ULN.
- Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≥3×ULN.
- Females who are pregnant (positive beta-human chorionic gonadotropin (β-hCG) test) or breastfeeding.
- Received treatment with an investigational drug within 30 days or 5 half-lives (whichever is longer) before Day 1/Baseline.
Trial locations and contacts
19 sites in 1 country.
19 sites in 1 country
Japan19 sites
Sobi Site 103
Bunkyō City, Toyko, 113-8603
Sobi Site 102
Chuo-shi, Yamanashi, 409-3898
Sobi Site 111
Fujisawa, Kanagawa, 251-8550
Sobi Site 115
Fukuyama-shi, Hiroshima, 720-2121
Sobi Site 114
Gifu, Gifu, 500-8513
Sobi Site 104
Hachiōji-shi, Tokyo, 192-0032
Sobi Site 107
Hirakata, Osaka, 573-1191
Sobi Site 109
Hiroshima, Hiroshima, 730-0052
Sobi Site 118
Iizuka-shi, Fukuoka, 820-8505
Sobi Site 113
Kanazawa, Ishikawa-ken, 920-8650
Sobi Site 116
Kitakyushu, Fukuoka, 802-8555
Sobi Site 108
Kobe, Hyōgo, 650-0047
Sobi Site 112
Kofu, Yamanashi, 400-8506
Sobi Site 119
Kumamoto, Kumamoto, 862-8655
Sobi Site 117
Kurume, Fukuoka, 830-8543
Sobi Site 101
Shiwa-gun, Iwata, 028-3695
Sobi Site 106
Suita, Osaka, 565-0871
Sobi Site 110
Tōon, Ehime, 791-0295
Sobi Site 105
Toyohashi, Aichi-ken, 441-8570
About this study
Official title: An Open-label Study to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Japanese Adults With Chronic Immune Thrombocytopenia
Evaluate the efficacy, safety, and PK of avatrombopag given for 26 weeks in Japanese adults with chronic immune thrombocytopenia (ITP).
Read the detailed description
This Phase 3, multicenter, open label study will evaluate the efficacy, safety, and population pharmacokinetics (PK) of avatrombopag in Japanese adults with chronic ITP. At least 19 subjects will be enrolled. The study will consist of 3 phases: Pre-enrollment, Primary Investigation, and Extension Phase until market authorization in Japan.
- Conditions
- Immune Thrombocytopenia
- Being tested
- Avatrombopag Oral Tablet
- Keywords
- ITP
- Medical subject headings
- Purpura, Thrombocytopenic, Idiopathic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Avatrombopag Oral TabletDrug
Also called Doptelet
Avatrombopag 20 mg given once daily (initial dose). Dosage adjustments were determined by the physician to maintain a platelet count between 50 x 10^9 to 200 x 10^9 as defined in the protocol and in accordance with overseas labeling.
| Study group | Role | What they receive |
|---|---|---|
| Avatrombopag | Other | Avatrombopag 20 mg oral tablet Receives: Drug: Avatrombopag Oral Tablet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cumulative Number of Weeks of Platelet Response
Cumulative number of weeks in which the platelet count is ≥50×10^9/L during 26 weeks of treatment in the absence of rescue therapy.
Measured: 26 weeks of active treatment
Secondary outcomes (1)
Response Rate at Day 8
Proportion of subjects with a platelet response ≥50×10^9/L at Day 8 in the absence of rescue therapy
Measured: Day 8
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 May 2022
- Study start15 Jun 2022
- Primary completion17 Jan 2024
- Study completion29 Oct 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Immune ThrombocytopeniaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sobi, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05369208
- Sponsor's protocol ID
- AVA-ITP-307
- Status last verified
- May 2026
- First submitted
- 21 Apr 2022
- Last updated
- 3 Jun 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Publications
Yamaguchi H, Iino M, Tomiyama Y, Kamiya H, Zhang J, Skuban N. (2025, October 10-12). One-year efficacy and safety of avatrombopag for chronic immune thrombocytopenia in Japanese adults [Conference presentation abstract]. 87th Annual Meeting of the Japanese Society of Hematology, Kobe, Hyogo, Japan.
Yamaguchi H, Iino M, Kowata S, Yamamoto R, Yamanouchi J, Imamura Y, Kirito K, Yokoyama K, Ito T, Ishikawa T, Shiratsuchi M, Tomiyama Y, Kamiya H, Zhang J, Jamieson BD. Correction: A phase 3 study of the efficacy and safety of avatrombopag in Japanese adults with chronic immune thrombocytopenia. Int J Hematol. 2025 Oct;122(4):623. doi: 10.1007/s12185-025-04054-5. No abstract available.
PubMed 40828490Yamaguchi H, Iino M, Kowata S, Yamamoto R, Yamanouchi J, Imamura Y, Kirito K, Yokoyama K, Ito T, Ishikawa T, Shiratsuchi M, Tomiyama Y, Kamiya H, Zhang J, Jamieson BD. A phase 3 study of the efficacy and safety of avatrombopag in Japanese adults with chronic immune thrombocytopenia. Int J Hematol. 2025 Oct;122(4):521-532. doi: 10.1007/s12185-025-04001-4. Epub 2025 May 20.
PubMed 40392465
Study at a glance
From the registry record, last updated by the sponsor on 3 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-label Study to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Japanese Adults With Chronic Immune Thrombocytopenia
- ClinicalTrials.gov ID
- NCT05369208
- Acronym / sponsor ID
- AVA-ITP-307
- Conditions
- Immune Thrombocytopenia
- Keywords
- ITP
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- Sobi, Inc.Industry (pharma, biotech, devices)
- Study start
- 15 Jun 2022 (actual)
- Primary completion
- 17 Jan 2024 (actual)
- Study completion
- 29 Oct 2025 (actual)
- First posted
- 11 May 2022 (actual)
- Results
- Posted 11 Feb 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Evaluate the efficacy, safety, and PK of avatrombopag given for 26 weeks in Japanese adults with chronic immune thrombocytopenia (ITP).
Detailed description
This Phase 3, multicenter, open label study will evaluate the efficacy, safety, and population pharmacokinetics (PK) of avatrombopag in Japanese adults with chronic ITP. At least 19 subjects will be enrolled. The study will consist of 3 phases: Pre-enrollment, Primary Investigation, and Extension Phase until market authorization in Japan.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Avatrombopag | Other | Drug: Avatrombopag Oral TabletAvatrombopag 20 mg oral tablet |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Subject has a confirmed diagnosis of chronic immune thrombocytopenia (ITP) (≥12 months duration) and has had an insufficient response to a previous ITP treatment, in the opinion of the Investigator.
- Subject has an average of 2 platelet counts <30×10^9/L (no single count can be >35×10^9/L). The 2 samples must be obtained ≥48 hours and ≤2 weeks apart.
Key exclusion criteria (19 listed)
- Subjects with known secondary immune thrombocytopenia (e.g., with known Helicobacter pylori-induced ITP, subjects infected with known human immunodeficiency virus (HIV) or hepatitis C virus (HCV) or subjects with known systemic lupus erythematosus).
- Subjects with known inherited thrombocytopenia (e.g., Myosin Heavy Chain 9 (MYH-9) disorders) or hereditary thrombophilic disorders (e.g., Factor V Leiden, antithrombin III deficiency).
- History of myelodysplastic syndrome (MDS).
- History of arterial or venous thrombosis.
- Subjects 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], angina, coronary artery stent placement, angioplasty, coronary artery bypass grafting).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Avatrombopag Oral TabletAlso: DopteletAvatrombopag 20 mg given once daily (initial dose). Dosage adjustments were determined by the physician to maintain a platelet count between 50 x 10^9 to 200 x 10^9 as defined in the protocol and in accordance with overseas labeling. | Drug | Avatrombopag |
Primary outcome
Cumulative Number of Weeks of Platelet Response
Time frame: 26 weeks of active treatment
Cumulative number of weeks in which the platelet count is ≥50×10^9/L during 26 weeks of treatment in the absence of rescue therapy.
1 secondary outcome
Response Rate at Day 8
Time frame: Day 8
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Jun 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Results publicationYamaguchi H, Iino M, Tomiyama Y, Kamiya H, Zhang J, Skuban N. (2025, October 10-12). One-year efficacy and safety of avatrombopag for chronic immune thrombocytopenia in Japanese adults [Conference presentation abstract]. 87th Annual Meeting of the Japanese Society of Hematology, Kobe, Hyogo, Japan.
- Results publication: PubMed 40828490Yamaguchi H, Iino M, Kowata S, Yamamoto R, Yamanouchi J, Imamura Y, Kirito K, Yokoyama K, Ito T, Ishikawa T, Shiratsuchi M, Tomiyama Y, Kamiya H, Zhang J, Jamieson BD. Correction: A phase 3 study of the efficacy and safety of avatrombopag in Japanese adults with chronic immune thrombocytopenia. Int J Hematol. 2025 Oct;122(4):623. doi: 10.1007/s12185-025-04054-5. No abstract available.
- Results publication: PubMed 40392465Yamaguchi H, Iino M, Kowata S, Yamamoto R, Yamanouchi J, Imamura Y, Kirito K, Yokoyama K, Ito T, Ishikawa T, Shiratsuchi M, Tomiyama Y, Kamiya H, Zhang J, Jamieson BD. A phase 3 study of the efficacy and safety of avatrombopag in Japanese adults with chronic immune thrombocytopenia. Int J Hematol. 2025 Oct;122(4):521-532. doi: 10.1007/s12185-025-04001-4. Epub 2025 May 20.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
19 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Avatrombopag Oral Tablet in people with Immune Thrombocytopenia, run by Sobi, Inc. at 19 sites in Japan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 19 sites in Japan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 11 Feb 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cumulative Number of Weeks of Platelet Response (time frame: 26 weeks of active treatment). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05369208, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Jun 2026.