CompletedNCT04132050Updated Aug 11, 2025Results posted

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

A Phase 3 interventional study of R788 and Placebo in Idiopathic Thrombocytopenic Purpura, sponsored by Kissei Pharmaceutical Co., Ltd.. Completed at 1 site in Japan. Open to participants aged 20 Years and older. Per ClinicalTrials.gov, last updated 2025-08-11.

Sponsored by Kissei Pharmaceutical Co., Ltd. · Phase 3, Interventional, and Treatment

Phase: Phase 3
Study type: Interventional
Enrollment: 34
Allocation: Randomized
Ages: 20 Years and older
Sex: All

Study 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.

Conditions studied

Idiopathic Thrombocytopenic Purpura

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Purpura, Thrombocytopenic, Idiopathic 517

In context

Purpura, Thrombocytopenic, Idiopathic

517 studies on the registry are indexed under Purpura, Thrombocytopenic, Idiopathic; 161 are open to participants now.

This study's enrollment of 34 is below the median of 60 across 381 interventional studies indexed under Purpura, Thrombocytopenic, Idiopathic.

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Lead sponsor

Kissei Pharmaceutical Co., Ltd. is the lead sponsor of 61 studies on the registry; 3 are open to participants now.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 20 Years and older
Sexes eligible: All
Accepts healthy volunteers: No

Inclusion criteria

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)

Exclusion criteria

Exclusion Criteria:

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

Study design

Phase: Phase 3
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel assignment
Masking: Double (Participant, Investigator)
Enrollment: 34 participants (actual)

Study arms

Experimental
R788
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).
Drug: R788
Placebo comparator
Placebo
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).
Drug: R788 · Drug: Placebo

Interventions

DrugR788
Oral administration
DrugPlacebo
Oral administration

What researchers measure

Primary outcomes

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)
Time frame: 24 weeks (Period I)

Other outcomes

Duration of Platelet Response
Period from the first measurement day on which a platelet count of ≥50000/μL for at least 28 consecutive days was achieved to the first measurement day on which platelet count fell below 50000/μL for at least 28 consecutive days
Time frame: R788 treatment period (maximum duration of exposure was 1184 days)

Results

Posted Aug 11, 2025

Participant flow

Seventy-two subjects were screened. Of these, 34 subjects considered eligible for the study were randomized to receive the investigational products. The number of subjects in Period I were 22 in the R788 group and 12 in the placebo group. The number of subjects who completed Period I was 10 in the R788 group and 4 in the placebo group.

Period I (Double-blind Period)

Participant flow — Period I (Double-blind Period)
Milestone	R788 Group	Placebo Group
Started	22	12
Completed	10	4
Not completed	12	8
Withdrew: Adverse event	3	0
Withdrew: Lack of efficacy	9	8

R788 Treatment Period

Participant flow — R788 Treatment Period
Milestone	R788 Group	Placebo Group
Started	33	0
Completed	22	0
Not completed	11	0
Withdrew: Adverse event	5	0
Withdrew: Lack of efficacy	5	0
Withdrew: Withdrawal by subject	1	0

Outcome measures

PrimaryAchievement 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)

Time frame:: 24 weeks (Period I)
Reported as:: Number · Percentage of participants

Achievement Rate of Stable Platelet Response
Percentage of participants	R788 Group	Placebo Group
Achievement Rate of Stable Platelet Response	36.4 (17.2 to 59.3)	0.0 (0.0 to 26.5)

Statistical analysis

R788 Group vs Placebo Group · Fisher Exact · p = 0.030 · Difference in percent of participants: 36.4 · 95% CI 3.1 to 59.3The difference in the achievement rate of "Stable platelet response" (= platelet count of ≥ 50000/μL at 4 or more of the 6 visits from Weeks 14 to 24) between two groups and its two-sided 95% CI were calculated.

Other pre-specifiedDuration of Platelet Response

Period from the first measurement day on which a platelet count of ≥50000/μL for at least 28 consecutive days was achieved to the first measurement day on which platelet count fell below 50000/μL for at least 28 consecutive days

Time frame:: R788 treatment period (maximum duration of exposure was 1184 days)
Reported as:: Median · days

Duration of Platelet Response
days	R788 Group
Duration of Platelet Response	392 (106 to 946)

Adverse events

Collected over - 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). Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
Group	Deaths	Serious	Other
R788 Group (Period I)	0/22 (0%)	2/22 (9.1%)	15/22 (68.2%)
Placebe Group (Period I)	0/12 (0%)	1/12 (8.3%)	7/12 (58.3%)
R788 Group (R788 Treatment Period)	0/33 (0%)	8/33 (24.2%)	32/33 (97%)

Most frequent serious events

Showing 10 of 14

Most frequent serious events
Event	R788 Group (Period I)	Placebe Group (Period I)	R788 Group (R788 Treatment Period)
Bile duct stoneHepatobiliary disorders	0/22	1/12	0/33
Procedural haemorrhageInjury, poisoning and procedural complications	0/22	1/12	0/33
ThrombocytopeniaBlood and lymphatic system disorders	1/22	0/12	1/33
DiarrhoeaGastrointestinal disorders	1/22	0/12	1/33
COVID-19Infections and infestations	0/22	0/12	1/33
CellulitisInfections and infestations	0/22	0/12	1/33
GastroenteritisInfections and infestations	0/22	0/12	1/33
Herpes zosterInfections and infestations	0/22	0/12	1/33
PericoronitisInfections and infestations	0/22	0/12	1/33
Atrial fibrillationCardiac disorders	0/22	0/12	1/33

Most frequent other events

Showing 10 of 42

Most frequent other events
Event	R788 Group (Period I)	Placebe Group (Period I)	R788 Group (R788 Treatment Period)
DiarrhoeaGastrointestinal disorders	9/22	0/12	13/33
HypertensionVascular disorders	7/22	1/12	11/33
COVID-19Infections and infestations	0/22	0/12	6/33
ConstipationGastrointestinal disorders	2/22	0/12	5/33
EczemaSkin and subcutaneous tissue disorders	2/22	0/12	5/33
Neutrophil count decreasedInvestigations	3/22	0/12	3/33
NasopharyngitisInfections and infestations	0/22	1/12	4/33
Liver function test increasedInvestigations	1/22	0/12	4/33
Herpes zosterInfections and infestations	1/22	0/12	3/33
NeutropeniaBlood and lymphatic system disorders	1/22	0/12	3/33

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)	R788 Group	Placebo Group	Total
<=18 years	0	0	0
Between 18 and 65 years	12	7	19
>=65 years	10	5	15

Age, Continuous
Age, Continuous(years)	R788 Group	Placebo Group	Total
Mean	59.6 ± 15.4	60.8 ± 15.4	60.0 ± 15.2

Sex: Female, Male
Sex: Female, Male(Participants)	R788 Group	Placebo Group	Total
Female	18	8	26
Male	4	4	8

Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)	R788 Group	Placebo Group	Total
Hispanic or Latino	0	0	0
Not Hispanic or Latino	22	12	34
Unknown or Not Reported	0	0	0

Race (NIH/OMB)
Race (NIH/OMB)(Participants)	R788 Group	Placebo Group	Total
American Indian or Alaska Native	0	0	0
Asian	22	12	34
Native Hawaiian or Other Pacific Islander	0	0	0
Black or African American	0	0	0
White	0	0	0
More than one race	0	0	0
Unknown or Not Reported	0	0	0

Region of Enrollment
Region of Enrollment(Participants)	R788 Group	Placebo Group	Total
Japan	22	12	34

Baseline platelet count
Baseline platelet count(cells/μL)	R788 Group	Placebo Group	Total
Median	19000 (3000 to 28000)	18000 (1000 to 27000)	18000 (1000 to 28000)

Time since ITP diagnosis
Time since ITP diagnosis(years)	R788 Group	Placebo Group	Total
Median	12 (1 to 41)	12 (1 to 38)	12 (1 to 41)

2 further baseline measures are reported on the registry.

Study locations

1 site

Research Site
Multiple Locations, Japan

References and documents

Study documents

Study protocol · Aug 28, 2019
Statistical analysis plan · Jun 24, 2022

Documents are hosted by the registry — open the source record to download them.

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Aug 11, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT04132050
Lead sponsor: Kissei Pharmaceutical Co., Ltd.
Responsible party: Sponsor
First posted: Oct 18, 2019
Start date: Dec 24, 2019
Primary completion: Dec 21, 2021
Completion: Sep 25, 2023
Results posted: Aug 11, 2025
Last update: Aug 11, 2025

Study contacts

Yoshitaka Shimizu

study director · Kissei Pharmaceutical Co., Ltd.

Oversight

FDA-regulated drug: No
FDA-regulated device: No

View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Dec 2023. You cannot join it, but the record below documents what was studied.

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