Anti-CD38 Monoclonal Antibody Combined With Rituximab in the Management of Primary Immune Thrombocytopenia (ITP)

A Single-arm, Open-label Phase II Clinical Study Evaluating the Efficacy of Rituximab Combined With Anti-CD38 Monoclonal Antibody in the Treatment of Primary Immune Thrombocytopenia (ITP)

This single-arm, open-label phase II study aim to evaluate the efficacy and safety of Daratumumab (anti-CD38 monoclonal antibody) combined with Rituximab in ITP patients.This study will be conducted in ITP patients who had not responded to or had relapsed after previous glucocorticoid treatment.

Study Overview

• Status: Recruiting
• Conditions: Immune Thrombocytopenia; Treatment
• Intervention / Treatment: Drug: Rituximab combined with Daratumumab（Anti-CD38 Monoclonal Antibody）

Detailed Description

Immune thrombocytopenia (ITP) is an organ-specific autoimmune disease, which is characterized by decreased platelet count and skin and mucosal bleeding. ITP is a kind of disease with increased platelet destruction and impaired platelet production caused by autoimmunity. Conventional treatment of adult ITP includes first-line glucocorticoid and immunoglobulin therapy, second line TPO and TPO receptor agonist, splenectomy and other immunosuppressive treatments (such as rituximab, vincristine, azathioprine, etc.). ITP is one of the most common hemorrhagic diseases. At present, the treatment response of ITP is not good, and a considerable number of patients need drug maintenance treatment, which seriously affects the quality of life of patients and increases the economic burden of patients. Therefore, there is still a lack of effective treatment for adult ITP, especially for recurrent and refractory ITP patients, which is one of the problems that have attracted more attention and need to be solved urgently.

The main pathogenesis of ITP is the loss of platelet autoantigen immune tolerance, which leads to abnormal activation of humoral and cellular immunity. It is characterized by antibody mediated platelet destruction and insufficient platelet production by megakaryocytes. The residual long-term autoreactive plasma cells may be a source of therapeutic resistance to autoimmune cytopenia. Antiplatelet specific plasma cells have been detected in the spleen of patients with rituximab refractory ITP. Therefore, the strategy of simply eliminating B cells may not work, because LLPC will continue to produce pathogenic antibodies. In view of this, we expected that the combination of rituximab and anti-CD38 monoclonal antibody could simultaneously eliminate CD20 positive B cells and LLPC, thereby profoundly reducing the production of pathogenic antibodies and increasing the efficacy of ITP treatment. Some patients in our center have been treated with this regimen in the past, with good efficacy and safety. Therefore, we planned to conduct a clinical study to evaluate the safety and efficacy of rituximab combined with Daratumumab（anti-CD38 monoclonal antibody） in relapsed adult patients with primary immune thrombocytopenia, in order to provide more treatment options for patients with ITP.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Yunfei Chen, MD; Phone Number: +8618502220788; Email: chenyunfei@ihcams.ac.cn
• Study Contact Backup: Name: Lei Zhang, MD; Phone Number: +8613502118379; Email: zhanglei1@ihcams.ac.cn

Study Locations

• China
  • Tianjin Municipality
    • Tianjin, Tianjin Municipality, China, 300020
      • Recruiting
      • Chinese Academy of Medical Science and Blood Disease Hospital
      • Contact: Lei Zhang, MD; Phone Number: +8602223909009; Email: zhanglei1@ihcams.ac.cn
      • Sub-Investigator: Ting Sun, MD
      • Contact: Yunfei Chen, MD; Phone Number: +8602223608180; Email: chenyunfei@ihcams.ac.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age ≥18 years, male or female.
• Before enrollment, the subjects have been clinically diagnosed with primary immune thrombocytopenia for no less than three months according to the American Society of Hematology guidelines 2011 Evidence-Based Practice Guideline (Neunert et al. 2011) or the International Consensus Report for the Investigation and Management of Primary Immune Thrombocytopenia (Provan et al. 2010), as applicable locally.
• Subjects have failed glucocorticoid therapy (either due to inefficacy, efficacy could not be maintained, or relapse). Subjects have failed at least one prior thrombopoietin receptor agonist therapy (such as rhTPO, eltrombopag, hetrombopag, etc.) in second-line treatment, as well as rituximab/anti-CD38 monoclonal antibody therapy (either due to inefficacy, efficacy could not be maintained, or relapse). Alternatively, subjects have experienced treatment failure or post-splenectomy relapse following splenectomy.
• Subjects with a platelet count of <30×10^9/L within the 24 hours prior to the first dose of the study drug; The mean platelet count of at least two separate assessments (at least 1 week apart) <30×10^9/L during the screening visit, and no platelet count > 35×10^9/L.
• ECOG performance status score of ≤2.
• Enrollment of subjects receiving maintenance therapy with a stable dosage is permitted, including glucocorticoids (≤0.5 mg/kg of prednisone or equivalent) or TPO receptor agonists. However, at the time of enrollment, subjects are restricted to using only one concomitant medication with a stable dose, and the concomitant medication must have been stable for a minimum of 4 weeks prior to the initial infusion of the study drug.
• For fertile female patients, a negative pregnancy test result is required. Fertile female and male patients must use effective contraception separately during the study and for 4 or 6 months after the cessation of study drug treatment.
• Subjects comprehensively understand and can adhere to the study protocol requirements and willingly signed the informed consent form.

Exclusion Criteria:

• Subjects allergic to CD20 monoclonal antibody or CD38 monoclonal antibody.
• Subjects who are diagnosed with autoimmune hemolytic anemia or various secondary thrombocytopenic disorders.
• Subjects with history of any thrombotic or embolic events or extensive and severe bleeding, such as hemoptysis, major upper gastrointestinal bleeding, intracranial hemorrhage, or the presence of sepsis or other irregular bleeding within the 12 months preceding the initiation of the first dose of study drug.
• Subjects who have participated in any other investigational drug studies (including vaccine studies) or been exposed to other investigational drugs within the first 4 weeks or 5 half-lives (whichever was longer) prior to the first dose of study drug.
• Subjects who have used anticoagulants or any agents with antiplatelet effects, such as aspirin, within 3 weeks prior to the first dose of study drug.
• Subjects who have received emergency treatment for ITP (e.g., methylprednisolone, platelet transfusion, intravenous immunoglobulin infusion, or thrombopoietin receptor agonist therapy) within 2 weeks prior to the first dose of study drug.
• Subjects who have been treated with medications including azathioprine, danazol, dapsone, cyclosporine A, tacrolimus, and sirolimus within 4 weeks prior to the first dose of study drug. Subjects who have been treated with CD20 monoclonal antibodies (e.g., rituximab), CD38 monoclonal antibodies, cyclophosphamide, vindesine, or similar medications within 3 months prior to the first dose of study drug.
• Subjects who have undergone splenectomy within 6 months prior to the first dose of study drug.
• Subjects who have received live vaccines within 4 weeks prior to the first dose of study drug, or plan to receive any live vaccines during the course of the study.
• Subjects who are diagnosed with Myelodysplastic syndromes (MDS); Subjects with a with a history of malignancy within the 5 years prior to screening (excluding completely cured in situ cervical cancer and non-metastatic skin squamous cell carcinoma or basal cell carcinoma).
• Subjects who have undergone allogeneic stem cell transplantation or organ transplantation.
• Subjects with a clinically significant medical history, as perceived by investigators, that will pose risks to subjects' safety during the study or potentially affect the safety or efficacy analyses, includes major clinical histories such as circulatory system abnormalities, endocrine system abnormalities, nervous system diseases, blood system diseases, immune system diseases, mental diseases and metabolic abnormalities and so on. e.g., subjects with acute myocardial infarction, unstable angina pectoris, or severe arrhythmias (multifocal ventricular premature contractions, ventricular tachycardia, or ventricular fibrillation) within the 6 months before screening ; New York Heart Association (NYHA) class III-IV heart failure; subjects who were known to have had moderate or severe persistent asthma or chronic obstructive pulmonary disease within the 5 years prior to screening, or whose condition was currently poorly controlled;
• Subjects with a history of severe recurrent or chronic infections, or acute infections requiring systemic treatment with antibiotics, antiviral drugs, antiparasitic drugs, anti-amoebic drugs, or antifungal drugs within 4 weeks prior to the first dose and during the screening period, or superficial skin infections requiring systemic treatment within one week prior to the first dose of study drug. Notably, after the resolution of the infection, the subject may be re-screened.
• Subjects with a history of known or suspected immunosuppression, including invasive opportunistic infections such as histoplasmosis, listeriosis, coccidioidomycosis, pneumocystis pneumonia, and aspergillosis, even if the infection has resolved; or unusually frequent, recurrent, or prolonged infections (as judged by the investigator).

• Significant laboratory abnormalities during screening included:

  1. Alanine aminotransferase or aspartate aminotransferase greater than three times the upper limit of normal (ULN).
  2. Total bilirubin greater than 1.5 times the ULN (note: subjects diagnosed with Gilbert syndrome based on medical records should not be excluded based on this criterion).
  3. absolute neutrophil count < 1500/mm3.
  4. hemoglobin < 9g/dL.
  5. IgG < 500 mg/dL.
  6. lymphocyte count < 500/mm3.
  7. Creatinine clearance (CrCl) < 30 mL/min (i.e., CrCl ≥30 mL/min is allowed)
• Positive for HIV antibodies or syphilis antibodies.
• Subjects test positive for Hepatitis B surface antigen (HBsAg) or subjects test positive for hepatitis B core antibody and HBV-DNA (through polymerase chain reaction testing), or subjects test positive for hepatitis C virus antibody and HCV-RNA during the screening period. Subjects with positive hepatitis B core antibody but negative HBV-DNA can be enrolled, with HBV-DNA monitoring every 4 weeks.
• Pregnant or lactating women, or those intending to conceive or breastfeed during the study; and male partners intending to induce pregnancy during the study.
• Any other conditions unsuitable for participation in this study, as assessed by the investigator.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Rituximab combined with Daratumumab（Anti-CD38 Monoclonal Antibody）; Rituximab (375mg/m2) was given once (day1) and a Daratumumab (16mg/kg) was given eight times (day8,15,22,29,36,43,50,57).	Drug: Rituximab combined with Daratumumab（Anti-CD38 Monoclonal Antibody）; For subjects in this study, rituximab (375mg/m2) was given once (day1) and Daratumumab（Anti-CD38 Monoclonal Antibody） (16mg/kg) was given eight times (day8,15,22,29,36,43,50,57).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall response rate at week 12	Overall response rate was defined as either partial response or complete response at week 12. Partial response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥30 to <100×10^9/L, with a minimum doubling from baseline and no bleeding. Complete response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥100×10^9/L, with no bleeding.	12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concomitant treatment	Changes in concomitant treatment at week12 compared with that at baseline	12 weeks
Changes in world health organization (WHO) bleeding scale	Changes in world health organization (WHO) bleeding scale without rescue treatment. Changes of every subject in WHO bleeding score after treatment according to the reported World Health Organization's Bleeding Scale. The WHO Bleeding Scale is a measure of bleeding severity with the following grades: grade 0 = no bleeding, grade 1= petechiae, grade 2= mild blood loss, grade 3 = gross blood loss, and grade 4 = debilitating blood loss.	1 year
Response at each visit	Response at each visit was defined as either overall response, partial response, complete response or the proportion of subjects with a platelet counts ≥ 50×10^9/L and at least twice the baseline level at each visit. Overall response rate was defined as either partial response or complete response. Partial response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥30 to <100×10^9/L, with a minimum doubling from baseline and no bleeding. Complete response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥100×10^9/L, with no bleeding.	1 year
Platelet counts at each visit	Platelet counts at each visit was defined as the platelet counts at each visit.	1 year
Time to the first platelet counts ≥30×10^9/L	Time to the first platelet counts ≥30×10^9/L was defined as time to first platelet counts ≥30×10^9/L with at least doubling from baseline	1 year
Time to the first platelet counts ≥50×10^9/L	Time to the first platelet counts ≥50×10^9/L was defined as time to first platelet counts ≥50×10^9/L with at least doubling from baseline	1 year
Time to the first platelet counts ≥100×10^9/L	Time to the first platelet counts ≥100×10^9/L was defined as time to first platelet counts ≥100×10^9/L	1 year
Cumulative durations of platelet counts ≥100×10^9/L, ≥50×10^9/L and ≥30×10^9/L, at least doubling from baseline	Cumulative durations of platelet counts≥100×10^9/L, ≥50×10^9/L and ≥30×10^9/L, at least doubling from baseline was defined as time from first two consecutive counts meeting criteria, to first two consecutive counts decreasing to below cut-off	1 year
Proportion of subjects receiving rescue treatment	Proportion of patients receiving rescue drugs within 12 weeks and throughout the trial	1 year
Overall response rate at week24	Overall response rate was defined as either partial response or complete response at week 24. Partial response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥30 to <100×10^9/L, with a minimum doubling from baseline and no bleeding. Complete response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥100×10^9/L, with no bleeding.	24 weeks
Overall response rate at week52	Overall response rate was defined as either partial response or complete response at week 52. Partial response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥30 to <100×10^9/L, with a minimum doubling from baseline and no bleeding. Complete response was characterised by at least two consecutive (≥7 days apart) platelet counts of ≥100×10^9/L, with no bleeding.	52 weeks
Adverse events assessment	Incidence, severity, and relationship of treatment emergent adverse events after treatment	1 year

Collaborators and Investigators

• Sponsor: Institute of Hematology & Blood Diseases Hospital, China

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: January 15, 2026
• First Submitted That Met QC Criteria: January 15, 2026
• First Posted (Actual): January 23, 2026

Study Record Updates

• Last Update Posted (Actual): January 23, 2026
• Last Update Submitted That Met QC Criteria: January 15, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cytopenia; Pathologic Processes; Autoimmune Diseases; Immune System Diseases; Hemorrhage; Skin Manifestations; Hematologic Diseases; Blood Coagulation Disorders; Hemorrhagic Disorders; Blood Platelet Disorders; Thrombotic Microangiopathies; Purpura, Thrombocytopenic; Purpura; Thrombocytopenia; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hemic and Lymphatic Diseases; Purpura, Thrombocytopenic, Idiopathic
• Other Study ID Numbers: IIT2024069

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Researchers qualified can request the dataset, including de-identified individual subject data. Data may be requested from PI from 12 months 36 months after study completion.
• IPD Sharing Time Frame: 12 months to 36 months after study completion
• IPD Sharing Access Criteria: Upon request to PI
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No