Porcine antilymphocyte globulin (p-ALG) plus cyclosporine A (CsA) treatment in acquired severe aplastic anemia: a retrospective multicenter analysis

Severe aplastic anemia (SAA) is a life-threatening bone marrow failure syndrome characterized by pancytopenia and hypocellular bone marrow. Antithymocyte globulin (ATG) is the drug of choice for immunosuppressive therapy (IST) in patients with SAA ineligible for allogeneic stem cell transplantation. This study aimed to evaluate the efficacy and safety profile of porcine antilymphocyte globulin (p-ALG) plus CsA in the treatment of acquired SAA. Clinical information of 69 SAA patients treated with p-ALG plus CsA was collected and retrospectively analyzed for early mortality, response rate, survival rate, side effects, and other complications. The median age at diagnosis was 27 years (range 14 to 52). The overall response rate was 76.8 % with a 90-day median response time (range 30 ~ 360 days). Overall response rates at 3, 6, 12, 18, and 24 months were 63.8, 73.9, 76.8, 75.4, and 75.4 %, respectively. The median follow-up time for surviving patients was 24 months (range 4 ~ 44 months) and the 2-year overall survival (OS) rate was 88.4 %. The disease-free survival (DFS) rate at 2 years was 85.5 %. Older age (≥45 years), very (v)SAA subgroup, and lower baseline absolute lymphocyte count (<1 × 10⁹/L) were independent unfavorable predictors of overall survival (p < 0.05). Less than one third of patients had serum sickness or allergic reaction during ALG therapy, but symptoms could easily be relieved by steroid treatment; 27.54 % had mild hepatic impairment. Taken together, p-ALG showed similar efficacy and safety profiles to rabbit or horse ATG in IST of acquired SAA. It can be a suitable alternative preparation for rabbit ATG with the great advantage of lower medical expenses.