Complications and treatment of patients with ß-thalassemia in France: results of the National Registry.

BACKGROUND: beta-thalassemia is a rare disease in France, encountered mainly in patients originating from Italy and North Africa. In the setting of the recent French plan for rare diseases, a National Registry for thalassemia has been developed since 2005. Epidemiological and clinical data have been collected on living patients with beta-thalassemia major or intermedia, including those who underwent hematopoietic stem cell transplantation. DESIGN AND METHODS: A standardized questionnaire was sent to clinicians throughout the national professional networks involved in the management of thalassemic patients and data were updated every 18 months. A cross-sectional study was performed in February 2009. RESULTS: Data on 378 patients (267 with thalassemia major) with a median age of 20 were recorded. Hematopoietic stem cell transplantation was performed in 52 patients. Stature, rates of parenthood, splenectomy, and cholecystectomy were no different between non-transplanted thalassemia major and thalassemia intermedia patients, after adjustment for age. Among the 215 non-transplanted thalassemia major patients, the median serum ferritin level was 1240 ng/mL and the rates of iron-related complications were 10%, 6%, 10% and 48% for cardiac failure, diabetes, hypothyroidism, and hypogonadism, respectively. From 2005 to 2008, a dramatic switch in chelation treatment, from deferoxamine to deferasirox, was observed. CONCLUSIONS: The rates of complications of iron overload in French thalassemia major patients appeared similar to those reported in other developed countries in which this condition is not endemic. There were no significant differences in height and parenthood rates between patients with the major and the intermedia forms of the disease, underlining the progress in clinical care. Future developments will focus on mortality and morbidity under oral chelation treatment.

A method to measure deferasirox in plasma using HPLC coupled with MS/MS detection and its potential application.

Iron overload resulting from transfusion dependency in some patients with chronic anaemia can be prevented by chelation. Deferasirox is an oral alternative to the well studied but inconvenient deferroxamine therapy. The pharmacokinetic parameters of this new drug suggest potential interindividual variability and patients might benefit from pharmacologic drug monitoring. We developed an liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS) method to quantify deferasirox in plasma. After protein precipitation, samples were injected onto an XTerra RP18 column with a gradient of acetonitrile and formiate buffer (4 mM, pH 3.0) with 5% methanol. Detection by electrospray ionization mass-spectrometry was performed using the multiple reaction monitoring mode. Sixty-three samples from patients treated with deferasirox were then analyzed to evaluate pharmacokinetic/pharmacodynamic relationships. Calibration curves were linear from 0.5 to 40 microg/mL. Interday and intraday precision were lower than 8.9% and 7.3%, respectively. Bias did not exceed 12.7%. Plasma iron overload did not interfere with analysis. Plasma drug concentrations of patients treated by deferasirox were compared with plasma ferritin, considered as a marker of treatment efficacy. No statistically significant correlation was observed, though higher ferritin concentrations (>1000 microg/L, n = 30) were observed in patients with lower mean deferasirox concentration (9.5 +/- 9.1 microg/mL). This simple method is suitable for routine monitoring of deferasirox concentrations in plasma as it requires very few steps and has a short runtime. It allows evaluation of patient compliance, drug-drug interactions, and further investigations of pharmacokinetic/pharmacodynamic relationships.

Analysis of risk factors for myelodysplasias, leukemias and death from infection among patients with congenital neutropenia. Experience of the French Severe Chronic Neutropenia Study Group.

BACKGROUND AND OBJECTIVES: The two main complications of severe chronic neutropenia are fatal sepsis and myelodysplasia/acute leukemia (MDS/AL). Granulocyte colony-stimulating factor (G-CSF) therapy has significantly reduced the frequency and severity of infections, but its possible influence on the risk of malignancy is not known. DESIGN AND METHODS: The French Severe Chronic Neutropenia (SCN) Registry has prospectively collected data since 1994 on 231 patients with various forms of SCN, namely severe congenital neutropenia (n=101), cyclic neutropenia (n=60), glycogen storage disease type Ib (GSDIb) (n=15) and Shwachman-Diamond syndrome (SDS)(n=55). The median overall follow-up is 11.1 years. Parameters of exposure to G-CSF therapy, such as the time averaged dose, follow up after first use of G-CSF, and the cumulative dose, have been recorded. RESULTS: Eight septic deaths occurred, of which 6 among patients with severe congenital neutropenia and 2 in patients with cyclic neutropenia; none of these 8 patients was receiving G-CSF therapy. No septic deaths occurred during G-CSF therapy. Thirteen cases of MDS/AL were recorded. The cumulative incidence of MDS/AL was 2.7% (SD 1.3%) at 10 years and 8.1% (SD 2.7%) at 20 years. INTERPRETATION AND CONCLUSIONS: Risk factors for MDS/AL were the diagnostic category, the severity of neutropenia, younger age at diagnosis, and strong exposure to G-CSF. MDS/AL only occurred in patients with severe congenital neutropenia and SDS. Owing to their particular susceptibility to infections, patients with severe congenital neutropenia had the strongest exposure to G-CSF; the risk of leukemia increased with the degree of G-CSF exposure in this subgroup.

Autosomal dominant STAT3 deficiency and hyper-IgE syndrome: molecular, cellular, and clinical features from a French national survey.

Autosomal dominant deficiency of signal transducer and activator of transcription 3 (STAT3) is the main genetic etiology of hyper-immunoglobulin (Ig) E syndrome. We documented the molecular, cellular, and clinical features of 60 patients with heterozygous STAT3 mutations from 47 kindreds followed in France. We identified 11 known and 13 new mutations of STAT3. Low levels of interleukin (IL)-6-dependent phosphorylation and nuclear translocation (or accumulation) of STAT3 were observed in Epstein-Barr virus-transformed B lymphocytes (EBV-B cells) from all STAT3-deficient patients tested. The immunologic phenotype was characterized by high serum IgE levels (96% of the patients), memory B-cell lymphopenia (94.5%), and hypereosinophilia (80%). A low proportion of IL-17A-producing circulating T cells was found in 14 of the 15 patients tested. Mucocutaneous infections were the most frequent, typically caused by Staphylococcus aureus (all patients) and Candida albicans (85%). Up to 90% of the patients had pneumonia, mostly caused by Staph. aureus (31%) or Streptococcus pneumoniae (30%). Recurrent pneumonia was associated with secondary bronchiectasis and pneumatocele (67%), as well as secondary aspergillosis (22%). Up to 92% of the patients had dermatitis and connective tissue abnormalities, with facial dysmorphism (95%), retention of decidual teeth (65%), osteopenia (50%), and hyperextensibility (50%). Four patients developed non-Hodgkin lymphoma. The clinical outcome was favorable, with 56 patients, including 43 adults, still alive at the end of study (mean age, 21 yr; range, 1 mo to 46 yr). Only 4 patients died, 3 from severe bacterial infection (aged 1, 15, and 29 yr, respectively). Antibiotic prophylaxis (90% of patients), antifungal prophylaxis (50%), and IgG infusions (53%) improved patient health, as demonstrated by the large decrease in pneumonia recurrence. Overall, the prognosis of STAT3 deficiency may be considered good, provided that multiple prophylactic measures, including IgG infusions, are implemented.