Porcine Anti-Lymphocyte Globulin, Cyclosporine A Plus Thrombopoietin Receptor Agonists Achieved Similar Efficacy and Survival Compared to Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Aplastic Anemia

Background: Immunosuppressive therapy (IST) with horse or rabbit anti-human thymocyte immunoglobulin (h-/r-ATG) and hematopoietic stem cell transplantation (HSCT) are two baseline treatments for severe aplastic anemia (SAA) and transfusion- dependent non-severe aplastic anemia (TD-NSAA) patients. Addition of thrombopoietin receptor agonists (TPO-RAs) to standard IST therapy (h-/r-ATG) has greatly improved the survival of SAA, whereas porcine anti-lymphocyte globulin (p-ALG) combined with TPO-RAs still had a matter of debate. Methods: We retrospectively compared the data of 48 AA patients in our center between 2020 and 2022, 23 AA patients received with p-ALG +/- TPO-RAs, 25 AA patients underwent matched sibling donor (MSD-) or haploidentical (haplo-) HSCT. Results: For patients in the HSCT group, the ORR was 90.9% which was significantly higher than that in the IST +/- TPO-RAs group (45.5%, P = 0.001) at 3 months; moreover, patients who underwent HSCT achieved faster transfusion independence, better CR rate, shorter time of recovery normal blood routine, and the percentage of normal blood routine (all P < 0.05) compared with IST +/- TPORAs group. However, the ORR were similary at 6 months in the two groups (95.5% vs 81.8% P = 0.342), with a median follow up of 19.8 months (range, 0.3-38.2 months), the 2-year FFS and OS in the two cohorts has no different. Subgroup analysis further indicated that the 2-year FFS and OS were similar between IST+TPO-RAs and haplo-HSCT subgroups, as well as in IST+TPO-RAs and MSDHSCT cohorts. Moreover, the first-time hospitalizations were much more expensive in the HSCT group than in the IST +/- TPO-RAs group (402 756 vs. 292 902 yuan, P = 0.002). Conclusion: P-ALG-based-IST +/- TPO-RAs is a good treatment option with similar FFS and OS compared to allo- HSCT for AA patients without the opportunity of HSCT.