Hematological differences between patients with different subtypes of sickle cell disease on hydroxyurea treatment

Evaluation of pharmacological efficacy and safety of hydroxyurea in sickle cell disease: Study of a pediatric cohort from Chhattisgarh, India

Sickle cell disease (SCD) is a disease of abnormal hemoglobin associated with severe clinical phenotype and recurrent complications. Hydroxyurea (HU) is one of the US-FDA approved and commonly used drug for the treatment of adult SCD patients with clinical -severity. However, its use in the pediatric groups remains atypical. Despite a high prevalence of the disease in the state Chhattisgarh, there is a lack of evidence supporting its use in pediatric patients. This study aimed to evaluate the pharmacological and clinical efficacy and safety of HU in a large pediatric cohort with SCD from Central India. The study cohort consisted of 164 SCD (138 Hb SS and 26 Hb S beta-thalassemia) children (≤14 years of age) on HU therapy, who were monitored for toxicity, hematological and clinical efficacy at baseline (Pre-HU) and after 24 months (Post-HU). The results highlight the beneficial effects of HU at a mean dose of 18.7 ± 7.0 mg/kg/day. A significant improvement was observed, not only in physical and clinical parameters but also in hematological parameters which include fetal hemoglobin (Hb F), total hemoglobin, hematocrit, mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) levels, when evaluated against the baseline. We did not observe any significant adverse effects during the treatment period. Similar results were obtained on independent analysis of Hb SS and Hb Sβ patients. These findings strengthen the beneficial effect of hydroxyurea in pediatric population also without any serious adverse effects and builds up ground for expanding its use under regular monitoring.

Influence of beta-cluster haplotypes, alpha-gene status and UGTA1 polymorphism on clinical and hematological data in sickle-cell disease children from French Guiana

OBJECTIVES

This cross-sectional study aimed to investigate the influence of haplotypes, alpha-gene status and UGTA1 polymorphism on the severity of sickle cell disease in children.

METHODS

This cross-sectional study was conducted between 2012 and 2014 at the Cayenne Hospital, in French Guiana. Acute clinical complications were grouped into (i) severe SCD defined by the presence of stroke and/or abnormal-transcranial Doppler (TCD), (ii) moderate SCD defined by the presence of at least three annual events requiring hospitalization and/or at least one acute chest syndrome, (iii) no severe SCD (in the absence of the precited events).

RESULTS

Among the 86 patients, 33.7% were female with a median age of 10 years (range: 6-12 years). The vast majority of patients had SCA (HbSS) phenotype (74.4%; n = 64). The severe haplotype was found in 40% of patients. 30% were BEN/BEN. Analysis of α-globin gene deletions revealed that 32 patients (37.2%) were heterozygous (loss of 2 genes in 2 cases and loss of 1 gene in 30 cases) for α-thalassemia (3.7 kb deletion). Homozygous (TA) n TA7/7 was found in 24 (28%). In the multivariate analysis, the factors associated with the severity of sickle cell disease were the first vaso-occlusive crisis before one year of age (OR 25, [95% CI = 6.0-107.0], p<0.001) and a baseline MCV >80 fL (OR 0.20 [95% CI = 0.04-0.96], p = 0.04). The area of the ROC curve was 0.90.

CONCLUSION

Prospective studies with greater statistical power would provide more knowledge on the relationship between UGT1A1 mutations and the clinical and hematological manifestations of SCA.

Hydroxyurea: Clinical and Hematological Effects in Patients With Sickle Cell Anemia

Background and Aim:

It is well known that hydroxyurea impacts on clinical and hematologic indices in sickle cell disease (SCD), we aimed to evaluate the effect of hydroxyurea on clinical and hematological improvement of sickle cell anemia.

Methods and Materials:

In this cohort study 48 patients with sickle cell disease were enrolled and pain crisis, severity of pain, acute chest syndrome, the number of hospitalization, the rate of transfusion, spleen size, total Hb, HbF levels, MCV, MCH were compared before and after treatment with HU 10 mg/kg/day/for one year.

Results:

In patients with Sickle cell disease Hu significantly decreased the rate of transfusion, hospitalization, spleen size and significantly increased Hb, RBC indices and HbF. Furthermore, we did not find any remarkable adverse effect related to HU during the one year follow up in patients.

Conclusion:

We demonstrated that in the course of one year hydroxyurea 10 mg/kg/day can significantly increase HbF, total hemoglobin and RBC indices without any notable side effect in patients with SCD.

α:Non-α and Gγ:Aγ globin chain ratios in thalassemia intermedia patients treated with hydroxyurea

OBJECTIVES

To elucidate the possible ways by which hydroxyurea molecules affect globin chain (α or β-like) synthesis.

METHODS

A total of 23 thalassemia intermedia patients (13 male and 10 female) aged between 5 and 26 years were treated for five months with 15 mg/(kg·day) of hydroxyurea. Hemoglobins electrophoresis and globin chain electrophoresis was performed on each sample at different time points before and during the treatment.

RESULTS

Fetal hemoglobin increased significantly in most patients and average episodes of transfusion decreased. Both Gγ and Aγ-globin chains increased significantly and α-globin:Nonα-globin chain as well as Gγ-globin:Aγ globin chains ratios decreased.

CONCLUSIONS

Improvement in α:non-α ratio and consequent decrease of free α-globin chain might be the cause of beneficial effects of hydroxyurea therapy. Two patients who felt better didn't show significant increase in their fetal hemoglobin level, and this is in contradiction with the hypothesis claiming that the HbF level increase is the cause of such therapeutic effect. In spite of the unclear mechanism of action of this drug, hydroxyurea therapy had noticeable impacts on thalassemia intermedia and also sickle cell disease and even patients suffering from thalassemia major.