BackgroundRomiplostim, a thrombopoietin (TPO) receptor antagonist, promotes tri-lineage hematopoiesis in patients with acquired aplastic anemia (AA). However, its efficacy as a first-line treatment in combination with an immunosuppressant, i.e., anti-thymocyte globulin (ATG) and cyclosporine (CSA), remains unexplored.ObjectiveTo assess the efficacy and safety of romiplostim in combination with ATG and CSA as first-line treatment in patients with AA.MethodA single-center, retrospective study of AA patients, where data of patients administered with ATG + CSA + romiplostim as a first-line treatment was included. Romiplostim 5 µg/kg weekly for one month; post that, the dose was increased to 10 µg/kg weekly for the next five months. The primary outcome involves the overall response rate and hematological response at baseline, three months, and six months.ResultData from 12 patients with a median age of 18 years was evaluated. At a median follow-up of six months, 25% achieved a complete response, 41.6% achieved a partial response, and 16.7% had no response. Improvement in tri-lineage hematopoietic response had been seen at six months from baseline, with improvement in absolute neutrophil count (ANC) and platelet count (PC) being the most significant, with an increase of >100% from baseline, followed by total leukocyte count (TLC) (75.13%) and hemoglobin (Hb) (66.07%) from baseline. Two deaths were reported during the treatment.ConclusionRomiplostim, in combination with ATG plus CSA, demonstrated clinically significant outcomes as a first-line treatment in patients with AA. Further studies are required to confirm these findings in larger populations to assess long-term outcomes.