Anti-CD38 Monoclonal Antibody Combined With Rituximab in the Management 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.

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.