Objective: This study focused on the efficacy and safety of thalidomide for patients with β-thalassemia in a multicenter trial.
Methods: Patients with non-transfusion-dependent thalassemia (NTDT) or transfusion-dependent thalassemia (TDT), who were unable to pursue conventional therapy with transfusion and chelation, were recruited over 3 years in three centers in southern China. We evaluated the efficacy and safety of thalidomide in the short-term (three months) and long-term follow-up (12 and 24 months). Response to thalidomide was defined as follows: Main Responder (MaR) showing an increase in hemoglobin (Hb) level of >2.0 g/dl or free from blood transfusion and Minor Responder (MiR) achieving elevated Hb level of 1.0-2.0 g/dl or ≥50% reduction in blood transfusion frequency.
Results: The overall response rate (ORR) was 93.5%, with MaR and MiR rates accounting for 62.9% and 30.6% in short-term follow-up. For patients with NTDT, the Hb level increased from a baseline mean of 6.8±1.1 g/dl to 9.7±1.9 g/dl (P<0.001). Elevated Hb was mainly attributable to increased fetal hemoglobin (HbF) levels. Among patients with TDT, while an increase in the average Hb concentration was observed, there was a significant drop in yearly transfusions from 20.7±7.7 to 5.8±6.8 blood units per year (P<0.001). The response of patients in both categories was sustained even after an average follow up of 14.6±9.6 months (3-37 months). Minimal side-effects were documented throughout, except peripheral neurotoxicity in one patient. Logistic regression analysis identified the ratio of HbF at baseline (P=0.038, OR=1.111, 95% CI: 1.006-1.226) as an independent risk factor for the primary response to thalidomide.
Conclusion: Thalidomide had significant therapeutic effects on patients with β-thalassemia with a sustained response. Peripheral neuropathy is one of the most feared complications. While these preliminary results support the potential long-term efficacy of thalidomide as a therapeutic agent for β-thalassemia, several issues need to be addressed before its application in the clinic.
Keywords: Efficacy; Fetal hemoglobin; Safety; Thalidomide; β-thalassemia.