Immune ThrombocytopeniaPhase 3NCT04516967
Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects With Immune Thrombocytopenia for ≥6 Months
A Phase 3 study testing Avatrombopag in people with Immune Thrombocytopenia, run by Sobi, Inc. at 62 sites in 9 countries.
Trial summary
A Phase 3b Study to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects with Immune Thrombocytopenia for ≥6 Months Read more about this study
- Who is it for?
- Ages 1 year to 17 years
- Conditions the study is for
- Immune Thrombocytopenia
- What is being tested?
- Avatrombopag
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 75 participants
- Where
- 62 sitesin 9 countries
- Study dates
- 5 Mar 2021to 28 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 1 year to 17 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- Male or female participants ≥1 and <18 years of age at Screening and Baseline with a diagnosis of primary ITP for ≥6 months duration and has had an insufficient response to a previous treatment, in the opinion of the Investigator.
- Participant has an average of 2 platelet counts <30×10^9/L with no single count >35×10^9/L in the screening period
Who cannot join
- Participants must not have a known history of secondary ITP, any history of arterial or venous thrombosis, including partial or complete thrombosis, known inherited thrombocytopenia, a history of myelodysplastic syndrome (MDS) or known history of congenital heart abnormalities or arrhythmias.
Trial locations and contacts
62 sites in 9 countries.
62 sites in 9 countries
United States21 sites
Site 116
Atlanta, Georgia, 30322
Site 111
Aurora, Colorado, 80045
Site 104
Boston, Massachusetts, 02115
Site 118
Charlotte, North Carolina, 28203
Site 106
Columbus, Ohio, 43205
Site 113
Durham, North Carolina, 27710
Site 117
Gainesville, Florida, 32610
Site 115
Houston, Texas, 77030
Site 114
Jackson, Mississippi, 39216
Site 102
Las Vegas, Nevada, 89135
Site 103
Long Beach, California, 90806
Site 105
Minneapolis, Minnesota, 55404
Site 108
Morristown, New Jersey, 07960
Site 119
Orange, California, 92868
Site 107
Peoria, Illinois, 61615
Site 121
Philadelphia, Pennsylvania, 19104
Site 112
Phoenix, Arizona, 85016
Site 110
Providence, Rhode Island, 02903
Site 109
Sacramento, California, 95817
Site 101
San Francisco, California, 94158
Site 120
Wilmington, Delaware, 19803
Turkey (Türkiye)10 sites
Site 701
Adana, 01330
Site 704
Ankara, 06230
Site 706
Antalya, 07059
Site 702
Antalya, 07160
Site 705
Denizli, 20160
Site 709
Istanbul, 34093
Site 710
Istanbul, 34093
Site 703
Istanbul, 34764
Site 707
Izmir, 35100
Site 708
Mersin, 33110
United Kingdom8 sites
Site 405
Birmingham, England, B4 6NH
Site 406
Cardiff, Wales, CF14 4XW
Site 408
Liverpool, England, L12 2AP
Site 403
London, England, SE5 9RS
Site 410
London, England, W12 0HS
Site 407
London, England, WC1N 3JH
Site 402
Manchester, England, M13 9WL
Site 401
Sheffield, England, S10 2TH
Russia7 sites
Site 907
Chelyabinsk, 454076
Site 904
Moscow, 117198
Site 906
Moscow, 117997
Site 901
Moscow, 119049
Site 902
Nizhny Novgorod, 603136
Site 905
Saint Petersburg, 197022
Site 903
Volgograd, 400138
Poland5 sites
Site 502
Bydgoszcz, Kuyavian-Pomeranian Voivodeship, 85-667
Site 504
Lodz, Łódź Voivodeship, 91-738
Site 501
Olsztyn, Warmian-Masurian Voivodeship, 10-561
Site 503
Warsaw, Masovian Voivodeship, 02-091
Site 505
Zabrze, Silesian Voivodeship, 41-800
Germany4 sites
Site 304
Berlin, State of Berlin, 13353
Site 301
Freiburg im Breisgau, Baden-Wurttemberg, 79106
Site 302
Hamburg, Free and Hanseatic City of Hamburg, 20246
Site 303
Kiel, Schleswig-Holstein, 24105
Hungary3 sites
Site 801
Budapest, 1094
Site 802
Miskolc, 3526
Site 803
Pécs, 7623
France2 sites
Site 202
Paris, Île-de-France Region, 75019
Site 201
Toulouse, Occitanie, 31059
Ukraine2 sites
Site 954
Kharkiv, Kharkiv Oblast, 61000
Site 952
Vinnytsia, 21029
About this study
Official title: Randomized, Double-blind, Placebo-controlled Study With Open-label Extension Phase to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects With Immune Thrombocytopenia for ≥6 Months
A Phase 3b Study to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects with Immune Thrombocytopenia for ≥6 Months
Read the detailed description
Subjects will be randomized in to blinded therapy of avatrombopag or placebo in a 3:1 ratio for a period of 12 weeks. Subjects who complete the 12 week treatment period and are eligible may continue to the open label extension phase which will last 2 years.
- Conditions
- Immune Thrombocytopenia
- Being tested
- Avatrombopag, Placebo
- 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.
AvatrombopagDrug
Also called Doptelet
Oral avatrombopag tablet or sprinkle capsule
PlaceboDrug
Placebo comparator tablet or sprinkle capsule
| Study group | Role | What they receive |
|---|---|---|
| Experimental: Avatrombopag Double Blind | Experimental | Study is 3:1 randomization ratio (avatrombopag to placebo). Investigational product administered orally once daily for 12 weeks Receives: Drug: Avatrombopag |
| Placebo Comparator:Placebo Double Blind | Placebo comparator | Study is 3:1 randomization ratio (avatrombopag to placebo). Investigational product administered orally once daily for 12 weeks Receives: Drug: Placebo |
| Avatrombopag Open Label Extension | Experimental | Investigational product administered orally for up to 2 years. Receives: Drug: Avatrombopag |
What is being measured
The primary outcome is the main question the study is designed to answer.
Durable Platelet Response
The proportion of subjects achieving at least 6 out of 8 weekly platelet counts ≥50×10^9/L during the last 8 weeks of the 12 week Treatment Period in the Core Phase, in the absence of rescue medication
Measured: Last 8 weeks of 12 week treatment regimen
Alternative Primary: Platelet Response
The proportion of subjects for whom at least 2 consecutive platelet assessments are ≥50×10^9/L over the 12 weeks of treatment in the Core Phase in the absence of rescue medication.
Measured: 12 weeks of treatment
Secondary outcomes (5)
Percentage of Weeks Platelet Count ≥50×10^9/L
The percentage of weeks subjects have a platelet count ≥50×10^9/L during 12 weeks of treatment in the Core Phase, in the absence of rescue therapy.
Measured: 12 weeks of treatment
Platelet Response at Day 8
The proportion of subjects with a platelet count ≥50×10^9/L at day 8, in the absence of rescue therapy.
Measured: Day 8
Percentage of Weeks Platelet Count Between ≥50×10^9/L and ≤150×10^9/L
The percentage of weeks subjects have a platelet count between ≥50×10^9/L and ≤150×10^9/L, during 12 weeks of treatment in the Core Phase, in the absence of rescue therapy.
Measured: 12 weeks of treatment
Rescue Medications
The proportion of subjects who require rescue medications during 12 weeks of treatment in the Core Phase of the study.
Measured: 12 weeks of treatment
Incidence of Any Bleeding Event (WHO Grade 1-4)
Overall incidence of bleeding events associated with ITP measured using the WHO Bleeding Scale (Grade 1-4).
Measured: 12 weeks of treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Aug 2020
- Study start5 Mar 2021
- Primary completion8 Nov 2023
- Study completion28 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 (7)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
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 75 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
- NCT04516967
- Sponsor's protocol ID
- AVA-PED-301
- Status last verified
- May 2026
- First submitted
- 14 Aug 2020
- Last updated
- 3 Jun 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Leblebisatan, G. G., Aydinok, Y., Äcenal, Ş., Grainger, J., Grimes, A., Lambert, M., Zhang, J., Jamieson, B., Vredenburg, M., & Kolodny, S. (2025). PB0364: Evaluation of efficacy and safety of avatrombopag in children with ITP based on disease duration. RPTH, 9(Suppl 2).
Leblebisatan, G. G., Aydinok, Y., Ünal Cangül, Ş., Grainger, J., Grimes, A., Lambert, M., Zhang, J., Jamieson, B., Vredenburg, M., & Kolodny, S. (2025). PB0348: Consistent response to avatrombopag for pediatric ITP across various baseline characteristics. RPTH, 9(Suppl 2).
Grace, R. F., Leblebisatan, G., Aydinok, Y., Ünal Cangül, Ş., Grainger, J., Zhang, J., Alkhori Franzén, L., & Skuban, N. (2025). PS2234: Efficacy and safety of avatrombopag for the treatment of pediatric immune thrombocytopenia in the open-label extension of a Phase 3, randomized, double-blind, placebo-controlled trial. HemaSphere, 9(Suppl 1), 4067.
Scott Kolodny, Rachael Grace, Göksel Leblebisatan, Yesim Aydinok, Şule Ünal, John Grainger, Amanda Grimes, Michelle Lambert, Jessica Zhang, Brian Jamieson, Michael Vredenburg. Baseline Correlates With Durability of Avatrombopag Response in Pediatric Immune Thrombocytopenia. Pediatr Blood Cancer. 2025;72(Suppl S94):e31765. Abstract [# 304].
Scott Kolodny, Rachael Grace, Göksel Leblebisatan, YesimAydinok, Şule Ünal, John Grainger, Amanda Grimes, Michele Lambert, Jessica Zhang, Brian Jamieson, Michael Vredenburg. Clinically Meaningful Response to Avatrombopag for Treatment of Pediatric Immune Thrombocytopenia. Pediatr Blood Cancer. 2025;72(Suppl S06):e31765. Abstract [# 2011].
Grace RF, Leblebisatan G, Aydinok Y, Unal S, Grainger JD, Zhang J, Smallwood L, de Leon E, Jamieson BD; AVA-PED-301 Study Group. Avatrombopag for the treatment of children and adolescents with immune thrombocytopenia (AVA-PED-301): a multicentre, randomised, double-blind, placebo-controlled, phase 3b study. Lancet Haematol. 2025 Jul;12(7):e494-e504. doi: 10.1016/S2352-3026(25)00107-3. Epub 2025 May 23.
PubMed 40418942Grace RF, Leblebisatan G, Aydinok Y, Unal S, Grainger JD, Zhang J, Smallwood L, de Leon E, Jamieson BD, DiRaimo J. Avatrombopag for treating children and adolescents with immune thrombocytopenia: a plain language summary. Expert Rev Hematol. 2026 Feb;19(2):107-116. doi: 10.1080/17474086.2025.2604524. Epub 2025 Dec 18.
PubMed 41411046
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
- Randomized, Double-blind, Placebo-controlled Study With Open-label Extension Phase to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects With Immune Thrombocytopenia for ≥6 Months
- ClinicalTrials.gov ID
- NCT04516967
- Acronym / sponsor ID
- AVA-PED-301
- Conditions
- Immune Thrombocytopenia
- Keywords
- ITP
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 75 participants (actual)
- Lead sponsor
- Sobi, Inc.Industry (pharma, biotech, devices)
- Study start
- 5 Mar 2021 (actual)
- Primary completion
- 8 Nov 2023 (actual)
- Study completion
- 28 Oct 2025 (actual)
- First posted
- 18 Aug 2020 (actual)
- Results
- Posted 17 Jan 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A Phase 3b Study to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects with Immune Thrombocytopenia for ≥6 Months
Detailed description
Subjects will be randomized in to blinded therapy of avatrombopag or placebo in a 3:1 ratio for a period of 12 weeks. Subjects who complete the 12 week treatment period and are eligible may continue to the open label extension phase which will last 2 years.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Experimental: Avatrombopag Double Blind | Experimental | Drug: AvatrombopagStudy is 3:1 randomization ratio (avatrombopag to placebo). Investigational product administered orally once daily for 12 weeks |
| Placebo Comparator:Placebo Double Blind | Placebo comparator | Drug: PlaceboStudy is 3:1 randomization ratio (avatrombopag to placebo). Investigational product administered orally once daily for 12 weeks |
| Avatrombopag Open Label Extension | Experimental | Drug: AvatrombopagInvestigational product administered orally for up to 2 years. |
Who may qualify
- Ages
- 1 year to 17 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (2 listed)
- Male or female participants ≥1 and <18 years of age at Screening and Baseline with a diagnosis of primary ITP for ≥6 months duration and has had an insufficient response to a previous treatment, in the opinion of the Investigator.
- Participant has an average of 2 platelet counts <30×10^9/L with no single count >35×10^9/L in the screening period
Key exclusion criteria (1 listed)
- Participants must not have a known history of secondary ITP, any history of arterial or venous thrombosis, including partial or complete thrombosis, known inherited thrombocytopenia, a history of myelodysplastic syndrome (MDS) or known history of congenital heart abnormalities or arrhythmias.
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 |
|---|---|---|
| AvatrombopagAlso: DopteletOral avatrombopag tablet or sprinkle capsule | Drug | Avatrombopag Open Label Extension, Experimental: Avatrombopag Double Blind |
| PlaceboPlacebo comparator tablet or sprinkle capsule | Drug | Placebo Comparator:Placebo Double Blind |
Primary outcome
Durable Platelet Response
Time frame: Last 8 weeks of 12 week treatment regimen
The proportion of subjects achieving at least 6 out of 8 weekly platelet counts ≥50×10^9/L during the last 8 weeks of the 12 week Treatment Period in the Core Phase, in the absence of rescue medication
Alternative Primary: Platelet Response
Time frame: 12 weeks of treatment
The proportion of subjects for whom at least 2 consecutive platelet assessments are ≥50×10^9/L over the 12 weeks of treatment in the Core Phase in the absence of rescue medication.
5 secondary outcomes
Percentage of Weeks Platelet Count ≥50×10^9/L
Time frame: 12 weeks of treatment
Platelet Response at Day 8
Time frame: Day 8
Percentage of Weeks Platelet Count Between ≥50×10^9/L and ≤150×10^9/L
Time frame: 12 weeks of treatment
Rescue Medications
Time frame: 12 weeks of treatment
Incidence of Any Bleeding Event (WHO Grade 1-4)
Time frame: 12 weeks of treatment
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 publicationLeblebisatan, G. G., Aydinok, Y., Äcenal, Ş., Grainger, J., Grimes, A., Lambert, M., Zhang, J., Jamieson, B., Vredenburg, M., & Kolodny, S. (2025). PB0364: Evaluation of efficacy and safety of avatrombopag in children with ITP based on disease duration. RPTH, 9(Suppl 2).
- Results publicationLeblebisatan, G. G., Aydinok, Y., Ünal Cangül, Ş., Grainger, J., Grimes, A., Lambert, M., Zhang, J., Jamieson, B., Vredenburg, M., & Kolodny, S. (2025). PB0348: Consistent response to avatrombopag for pediatric ITP across various baseline characteristics. RPTH, 9(Suppl 2).
- Results publicationGrace, R. F., Leblebisatan, G., Aydinok, Y., Ünal Cangül, Ş., Grainger, J., Zhang, J., Alkhori Franzén, L., & Skuban, N. (2025). PS2234: Efficacy and safety of avatrombopag for the treatment of pediatric immune thrombocytopenia in the open-label extension of a Phase 3, randomized, double-blind, placebo-controlled trial. HemaSphere, 9(Suppl 1), 4067.
- Results publicationScott Kolodny, Rachael Grace, Göksel Leblebisatan, Yesim Aydinok, Şule Ünal, John Grainger, Amanda Grimes, Michelle Lambert, Jessica Zhang, Brian Jamieson, Michael Vredenburg. Baseline Correlates With Durability of Avatrombopag Response in Pediatric Immune Thrombocytopenia. Pediatr Blood Cancer. 2025;72(Suppl S94):e31765. Abstract [# 304].
- Results publicationScott Kolodny, Rachael Grace, Göksel Leblebisatan, YesimAydinok, Şule Ünal, John Grainger, Amanda Grimes, Michele Lambert, Jessica Zhang, Brian Jamieson, Michael Vredenburg. Clinically Meaningful Response to Avatrombopag for Treatment of Pediatric Immune Thrombocytopenia. Pediatr Blood Cancer. 2025;72(Suppl S06):e31765. Abstract [# 2011].
- Results publication: PubMed 40418942Grace RF, Leblebisatan G, Aydinok Y, Unal S, Grainger JD, Zhang J, Smallwood L, de Leon E, Jamieson BD; AVA-PED-301 Study Group. Avatrombopag for the treatment of children and adolescents with immune thrombocytopenia (AVA-PED-301): a multicentre, randomised, double-blind, placebo-controlled, phase 3b study. Lancet Haematol. 2025 Jul;12(7):e494-e504. doi: 10.1016/S2352-3026(25)00107-3. Epub 2025 May 23.
- Results publication: PubMed 41411046Grace RF, Leblebisatan G, Aydinok Y, Unal S, Grainger JD, Zhang J, Smallwood L, de Leon E, Jamieson BD, DiRaimo J. Avatrombopag for treating children and adolescents with immune thrombocytopenia: a plain language summary. Expert Rev Hematol. 2026 Feb;19(2):107-116. doi: 10.1080/17474086.2025.2604524. Epub 2025 Dec 18.
- Individual participant dataSharing planned: No
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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.
62 sites in 9 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Avatrombopag in people with Immune Thrombocytopenia, run by Sobi, Inc. at 62 sites in 9 countries.
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 1 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 62 sites in United States, Turkey (Türkiye), United Kingdom, Russia, Poland and 4 more countries. 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. Some participants in this study may receive a placebo. 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 17 Jan 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?
Durable Platelet Response (time frame: Last 8 weeks of 12 week treatment regimen). The study lists 2 primary outcomes in all. 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 NCT04516967, which also lists 7 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.