A single-center, open-label, off-label use investigator-initiated clinical study to explore the clinical activity and safety of daratumumab in adult ITP patients who have not responded adequately or relapsed after first-line treatment and at least one second-line therapy including rituximab and/or TPO-RA.
Primary immune thrombocytopenia is an autoimmune disease associated with a reduced peripheral blood platelet count. The first-line treatment is corticosteroids. Splenectomy, rituximab, and thrombopoietin receptor agonists (TPO RAs, such as Etrapopar and Romistine) are commonly used as second-line therapy. However, many of the treatments used achieve few lasting remissions. About 20% - 30% of patients have inadequate or no response to first-line and second-line treatment, and would develop into recurrent/refractory (r/r) ITP. A branch of pathogenesis for ITP has been revealed that plasma cells secrete pathogenic antibodies directed against platelet and red blood cell antigens. Antiplatelet specific plasma cells have been detected in the spleen of patients with rituximab refractory ITP. In those refractory cases, persistent autoreactive long-lived plasma cells in the bone marrow could explain treatment failure. Daratumumab, an anti-CD38 monoclonal antibody developed to target tumoral plasma cells in multiple myeloma, was recently found to be effective in antibody-mediated diseases, such as autoimmune cytopenia following hematopoietic stem cell transplantation, systemic lupus and also ITP. This study will evaluate the safety and biologic activity of Daratumumab in r/r primary ITP who fail to respond to at least one previous second-line therapy. The study will enroll approximately 20 participants. This trial will be conducted in China. All participants will be followed for at least 16 weeks after the 8 weeks of treatment.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
60
intravenous daratumumab administration
Chinese Academy of Medical Science and Blood Disease Hospital
Tianjin, Tianjin Municipality, China
Evaluate of response after daratumumab treatment
The proportion of patients with 2 consecutive platelet counts of ≥ 50×109/L within 8 weeks
Time frame: 8 weeks
Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] of daratumumab
Incidence, severity, and relationship of treatment emergent adverse events after daratumumab treatment
Time frame: 24 weeks
The proportion of patients with ≥2 consecutive platelet counts (separated by ≥7 days) of ≥30 × 109/L and a ≥2-fold increase from the baseline count within 8 weeks
The proportion of patients with ≥2 consecutive platelet counts (separated by ≥7 days) of ≥30 × 109/L and a ≥2-fold increase from the baseline count within 8 weeks.
Time frame: 8 weeks
Time to first platelet count of ≥50 × 109/L without salvage therapy.
Time to first platelet count of ≥50 × 109/L without salvage therapy.
Time frame: 24 weeks
Overall response rate at week 8 and week 24
Complete response (CR) : 2 or more consecutive monitored platelet counts ≥100 × 109/L without bleeding symptoms,with an interval of at least 7 days; Partial response (PR) : 2 or more consecutive monitored platelet counts ≥30 × 109/L, at least a double baseline count (separated by ≥7 days), and no bleeding symptoms. Overall response (OR) : CR or PR.
Time frame: 24 weeks
Complete response rate at week 8 and week 24
Complete response (CR) : 2 or more consecutive monitored platelet counts ≥100 × 109/L without bleeding symptoms,with an interval of at least 7 days.
Time frame: 24 weeks
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Cumulative response duration of platelet count of ≥30 × 109/L and a platelet count doubling from the baseline within 24 weeks
Cumulative response duration of platelet count of ≥30 × 109/L and a platelet count doubling from the baseline within 24 weeks.
Time frame: 24 weeks
Durable sustained platelet count response rate
Durable sustained platelet count response rate is defined as the proportion of subjects with platelet counts of ≥30 × 109/L for at least six of the eight visits between weeks 17 and 24 of the study.
Time frame: 24 weeks
WHO bleeding score at baseline and at week 8 and 24 after treatment
WHO bleeding score at baseline and at week 8 and 24 after treatment. 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.
Time frame: 24 weeks
The proportion of subjects with concomitant medication reduction or discontinuation
The proportion of subjects with concomitant medication reduction or discontinuation within 24 weeks.
Time frame: 24 weeks
The proportion of subjects receiving rescue medications
The proportion of subjects receiving rescue medications within 24 weeks.
Time frame: 24 weeks
Changes in immunoglobulin levels
Changes in immunoglobulin levels before and after treatment
Time frame: 24 weeks