Anti-CD38 Monoclonal Antibody Is a Salvage Regimen in Relapsed/Refractory Aplastic Anemia

Background: About half of patients with aplastic anemia (AA) are in a refractory or relapsed state after first-line immunosuppressive therapy (IST). The persistent pancytopenia in relapsed/refractory AA (r/r AA) patients affects their quality of life and even is life-threatening. Hematopoietic stem cell transplantation, second course of IST and TPO receptor agonist ameliorate the disease in more than half of these people. But patients not eligible for these treatments are still lack of proper choice. Methods: We conducted a retrospective study to evaluate the efficacy and safety of daratumumab, a monoclonal CD38 antibody, in treating r/r AA. Daratumumab was given 8mg/kg weekly for 4 weeks to 10 r/r AA patients. Ciclosporin or danazol was given as concurrent treatment to 5 patients who had already received the drug for at least 6 months. Patients achieved response during 12 weeks would receive the second cycle treatment. Results: The overall response rate was 5 of 10 patients (50%) with multilineage responses in 4 of them. The median response time was 6 weeks (range, 5-10 weeks). Patients sustained response with a median 5.5 months duration time (range, 2-13.5 months), including 2 responders still during follow-up. Infection and infusion-related reaction are the most common adverse events with an 80% and 70% incidence respectively, including 1 patient with grade 3/4 infection. Incidence of hematologic adverse events was 50% and 80% of them were grade 3/4, and the median time of recovering to grade 1/2 was 3 days (range, 1-15 days). Conclusion: Anti-CD38 monoclonal antibody may be a promising option for r/r AA patients with an appreciable efficacy, rapid response, and accepted adverse events.