Idiopathic Thrombocytopenic PurpuraPhase 3NCT04132050

A Clinical Study in Patients With Chronic Idiopathic Thrombocytopenic Purpura in R788

A Phase 3 study testing R788 in people with Idiopathic Thrombocytopenic Purpura, run by Kissei Pharmaceutical Co., Ltd. at 1 site in Japan.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

Search all trials

Trial summary

The purpose of this study is to investigate the efficacy, safety and pharmacokinetics of R788 compared with placebo, and to investigate the safety and efficacy of long term dosing of R788 in patients with chronic idiopathic thrombocytopenic purpura. Read more about this study

Who is it for?: Ages 20 years and older
Conditions the study is for: Idiopathic Thrombocytopenic Purpura
What is being tested?: R788
Type of treatment: Pill or oral medicine
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 34 participants
Where: 1 siteJapan
Study dates: 24 Dec 2019to 25 Sep 2023
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 20 years and older
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

Japanese patients
Patients diagnosed with idiopathic thrombocytopenic purpura at least 6 months before acquisition of consent
Patients with a platelet count averages <30000/μL during screening period. Each platelet count should not exceed 35000/μL.
Patients who have used and failed or who were intolerant at least 1 typical regimen for the treatment of ITP before informed consent (with or without splenectomy)

Who cannot join

Patients with thrombocytopenia associated with other disease
Patients with autoimmune hemolytic anemia
Patients with poorly controlled hypertension
Patients with a history or active coagulopathy

Trial locations and contacts

1 site in 1 country.

Japan1 site

Research Site
Multiple Locations

Other trials in Japan

About this study

Official title: A Phase III Study in Patients With Chronic Idiopathic Thrombocytopenic Purpura in R788

Conditions: Idiopathic Thrombocytopenic Purpura
Being tested: R788, Placebo
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.

R788Drug
Oral administration
PlaceboDrug
Oral administration

Study groups in NCT04132050
Study group	Role	What they receive
R788	Experimental	Patients are administered R788 for 24 weeks (double-blind period), followed by R788 for up to 52 weeks (open-label period). Patients who have completed open-label period and meet the criteria are eligible to continue R788 treatment over a 3 year period (extension - period). Receives: Drug: R788
Placebo	Placebo comparator	Patients are administered Placebo for 24 weeks (double-blind period), followed by R788 for up to 28 weeks (open-label period). Patients who have completed open-label period and meet the criteria are eligible to continue R788 treatment over a 3 year period (extension - period). Receives: Drug: R788; Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

Achievement Rate of Stable Platelet Response
The percentage of subjects who achieved stable platelet response (defined as a platelet count of ≥50000/μL at 4 or more of the 6 visits from Weeks 14 to 24)
Measured: 24 weeks (Period I)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

24 Dec 201925 Sep 2023

First posted18 Oct 2019
Study start24 Dec 2019
Primary completion21 Dec 2021
Study completion25 Sep 2023

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.
Other trials for Idiopathic Thrombocytopenic PurpuraStudies 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: 34 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04132050
Sponsor's protocol ID: R788-1301
Status last verified: Dec 2023
First submitted: 15 Oct 2019
Last updated: 11 Aug 2025
Results posted: Yes, on ClinicalTrials.gov
FDA-regulated drug: No
FDA-regulated device: No

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

RecruitingPhase 2
A Study to Assess the Tolerability of Ianalumab (VAY736) With Investigator's Choice Thrombopoietin Receptor Agonist (IC TPO-RA) in Patients With Primary Immune Thrombocytopenia (ITP)
Primary Immune Thrombocytopenia (ITP), Primary Evans Syndrome (ES)
RecruitingPhase 1/2
A Study of Pirtobrutinib in Participants With Immune Thrombocytopenia
Immune Thrombocytopenia (ITP)
RecruitingPhase 3
A Study of Mezagitamab in Adults With Chronic Primary Immune Thrombocytopenia
Immune Thrombocytopenic Purpura (ITP)
RecruitingPhase 2
Study to Assess the Safety and Tolerability of Tafasitamab in Adult Participants With Primary Autoimmune Blood Cell Disorders
Immune Thrombocytopenia
RecruitingPhase 3
A Follow-up Study of Mezagitamab in Adults With Chronic Primary Immune Thrombocytopenia
Immune Thrombocytopenic Purpura (ITP)

All Idiopathic Thrombocytopenic Purpura trials

Study at a glance

From the registry record, last updated by the sponsor on 11 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Phase III Study in Patients With Chronic Idiopathic Thrombocytopenic Purpura in R788
ClinicalTrials.gov ID: NCT04132050
Acronym / sponsor ID: R788-1301
Conditions: Idiopathic Thrombocytopenic Purpura
Phase: Phase 3
Study type: Interventional
Recruitment status: Completed
Enrolment: 34 participants (actual)
Lead sponsor: Kissei Pharmaceutical Co., Ltd.Industry (pharma, biotech, devices)
Study start: 24 Dec 2019 (actual)
Primary completion: 21 Dec 2021 (actual)
Study completion: 25 Sep 2023 (actual)
First posted: 18 Oct 2019 (actual)
Results: Posted 11 Aug 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Double blind (participant, investigator)
Number of arms: 2

Arm	Type	Receives
R788	Experimental	Drug: R788Patients are administered R788 for 24 weeks (double-blind period), followed by R788 for up to 52 weeks (open-label period). Patients who have completed open-label period and meet the criteria are eligible to continue R788 treatment over a 3 year period (extension - period).
Placebo	Placebo comparator	Drug: R788, Drug: PlaceboPatients are administered Placebo for 24 weeks (double-blind period), followed by R788 for up to 28 weeks (open-label period). Patients who have completed open-label period and meet the criteria are eligible to continue R788 treatment over a 3 year period (extension - period).

Who may qualify

Ages: 20 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (4 listed)

Japanese patients
Patients diagnosed with idiopathic thrombocytopenic purpura at least 6 months before acquisition of consent
Patients with a platelet count averages <30000/μL during screening period. Each platelet count should not exceed 35000/μL.
Patients who have used and failed or who were intolerant at least 1 typical regimen for the treatment of ITP before informed consent (with or without splenectomy)

Key exclusion criteria (4 listed)

Patients with thrombocytopenia associated with other disease
Patients with autoimmune hemolytic anemia
Patients with poorly controlled hypertension
Patients with a history or active coagulopathy

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
R788Oral administration	Drug	Placebo, R788
PlaceboOral administration	Drug	Placebo

Primary outcome

Achievement Rate of Stable Platelet Response
Time frame: 24 weeks (Period I)
The percentage of subjects who achieved stable platelet response (defined as a platelet count of ≥50000/μL at 4 or more of the 6 visits from Weeks 14 to 24)

Results and safety

Results posted to the registry on 11 Aug 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
R788 Group	22	10
Placebo Group	12	4

Primary outcome: Achievement Rate of Stable Platelet Response

Time frame: 24 weeks (Period I). Number (95% Confidence Interval). Unit: Percentage of participants

Measure	R788 Group n = 22	Placebo Group n = 12
Value	36.4 (17.2 to 59.3)	0.0 (0.0 to 26.5)

R788 Group vs Placebo Group: Difference in Percent of Participants: 36.4 (95% CI 3.1 to 59.3), p = 0.030, Fisher Exact

Adverse events

Time frame: - Period I: 24 weeks - R788 treatment period: Period I (24 weeks) + Period II (28 weeks) + Period III (Period III and the period of post-marketing clinical study: Maximum 845 days). Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
R788 Group (Period I)	2 of 22 (9.1%)	15 of 22 (68.2%)	0 of 22
Placebe Group (Period I)	1 of 12 (8.3%)	7 of 12 (58.3%)	0 of 12
R788 Group (R788 Treatment Period)	8 of 33 (24.2%)	32 of 33 (97%)	0 of 33

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 11 Aug 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.

Related trials for Idiopathic Thrombocytopenic Purpura

RecruitingPhase 2
A Study to Assess the Tolerability of Ianalumab (VAY736) With Investigator's Choice Thrombopoietin Receptor Agonist (IC TPO-RA) in Patients With Primary Immune Thrombocytopenia (ITP)
Primary Immune Thrombocytopenia (ITP), Primary Evans Syndrome (ES)
RecruitingPhase 1/2
A Study of Pirtobrutinib in Participants With Immune Thrombocytopenia
Immune Thrombocytopenia (ITP)
RecruitingPhase 3
A Study of Mezagitamab in Adults With Chronic Primary Immune Thrombocytopenia
Immune Thrombocytopenic Purpura (ITP)
RecruitingPhase 2
Study to Assess the Safety and Tolerability of Tafasitamab in Adult Participants With Primary Autoimmune Blood Cell Disorders
Immune Thrombocytopenia
RecruitingPhase 3
A Follow-up Study of Mezagitamab in Adults With Chronic Primary Immune Thrombocytopenia
Immune Thrombocytopenic Purpura (ITP)

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.

Yoshitaka Shimizu study director

Kissei Pharmaceutical Co., Ltd.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing R788 in people with Idiopathic Thrombocytopenic Purpura, run by Kissei Pharmaceutical Co., Ltd. at 1 site 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 4 inclusion and 4 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 11 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site 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. 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 11 Aug 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?

Achievement Rate of Stable Platelet Response (time frame: 24 weeks (Period I)). 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 NCT04132050.

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 11 Aug 2025.