Poster Session I: Thalassemias
In 2005, a national registry was established to collect epidemiological and clinical data for patients with beta-thalassemia living in France. The objective of this data collection was to better understand patient characteristics, treatment patterns, and clinical outcomes among patients followed in France. Completeness is achieved by cross-checking with different sources. The registry collects data on patients with beta-thalassemia major TM) (defined as requiring ≥8 RBC transfusions per year) and thalassemia intermedia (TI). Data is updated every 2 years.
Here, we first describe the whole population included in the registry with the number and causes of death during the period 2005-2017; second, we focus on a sub-group of transfusion-dependent thalassemia (TDT) patients followed from 2009/2010 for 2 to 6 years.
Patients were included between 01/01/2005 and 31/01/2019. A cross sectional study and a longitudinal study were performed in February 2019. For the longitudinal study, TDT (either TM or TI) patients included in the registry before 2010 were selected. Baseline data corresponds to data collected in 2009 or 2010 and 2-, 4-, and 6-year data corresponds to data collected during follow-up. Iron overload was assessed by serum ferritin (SF) level and hepatic and cardiac MRI. Iron measurement risk category cutoffs based on published literature were ≤20 ms (intermediate risk) and ≤10 ms (high risk) for cardiac T2* and ≥7 mg/gDW (intermediate risk) and ≥15 mg/gDW (high risk) for liver iron content (LIC) by MRI.
A total of 666 patients (441 with TM) with a median age of 23, was included in the registry since 2005. HSC transplantation was performed in 116 patients. Genotype was available for 298 patients and is constituted of 2 beta0-mutations in 2/3 of the cases. During the period of follow-up (01/01/2005 to 31/01/2019) 34 patients died (8.5 deaths for 1000 patients-years), 27 patients with TM and 7 with TI. The main causes of death were heart failure (14) and infections (10).
Regarding TDT patients followed for up to 6 years, 272 patients with TDT and at least a 2-year follow-up were identified at baseline. At 6 years, data was available for 198 of them. The % of patients who had a hepatic MRI increased from 51 to 65% and a cardiac MRI, from 30.5 to 52.5%. At baseline, 37% and 17% of patients presented with intermediate or high SF respectively, 25.8 and 38.2% with intermediate or high liver iron concentration. High myocardial risk was evidenced in 8.5% of the patients. After 6 years of follow up, the proportions remained identical in the intermediate risk group and slightly decreased in the high-risk group (11.3, 24.9 and 4.8% for SF level, LIC and T2* respectively).
After 6 years, the cumulative proportion surviving without any complication (among the following: death, heart failure, arrhythmia, hepatic failure, hypothyroidism, diabetes) is 79.8% in the group of patients with age up to 12.
Deferasirox remains the most frequent chelation agent used in monotherapy with 65% of patients using this agent at baseline and 57% after 6 years. Deferiprone use increased from 11% to 22% during the same period. A Combination of 2 chelators increased from 10 to 15%.
This real-world study provides information about treatment patterns and clinical outcomes of patients with Thalassemia enrolled in the French thalassemia registry. Some patients with TDT continued to experience high liver and cardiac iron levels and related complications, despite ongoing treatment with chelating agents.