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.
A single-center, open-label, off-label use investigator-initiated clinical study with safety run-in 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.