Recombinant erythropoietin in autoimmune hemolytic anemia with inadequate bone marrow response: a prospective analysis.

Up to 30% of patients with autoimmune hemolytic anemia (AIHA) show inadequate bone marrow compensatory response with inappropriately low levels of reticulocytes and endogenous erythropoietin. Ineffective bone marrow compensation is associated with more severe anemia, transfusion need, and hospital admission and treatment with recombinant erythropoietin (rEPO) may be beneficial. Here we prospectively analyzed the efficacy and safety of rEPO in a single-center cohort of 47 AIHA patients with anemia and inadequate reticulocytosis and endogenous erythropoietin at baseline. Epoetin alpha 40,000 IU/week were administered subcutaneously until Hb>11 g/dL and then tapered off. Overall response was 55% at 15 days, 74% at 1 month, 74% at 3 months, 80% at 6, and 91% at 12 months. Consistently, Hb values significantly increased from baseline to each subsequent timepoint (p<0.001) with a median increase of +1.4 g/dL, +2.4, +3.4, +3.8, and +4.4 g/dL, respectively. Transfusion needs reduced from 30% to <10% at 15 days and thereafter (p<0.001). Concomitant medications included prednisone/methylprednisolone (N=40, stable since > 2 weeks from enrolment), mycophenolate mofetil (N=1, ongoing since >3 months from enrolment), and rituximab (N=7 cold agglutinin disease patients from day 8). No association between concomitant medications and response to rEPO was found. Treatment was generally safe without rEPO-related severe adverse events. The comparison with an AIHA population not treated with rEPO showed a significant benefit of rEPO at 15 days and 1 month on response/Hb increase. These data support the use of rEPO as add on to standard immunosuppression in AIHA with inadequate bone marrow compensation. ClinicalTrials.gov: NCT05931718.