The Effect and Side Effect of Hydroxyurea Therapy on Patients With β-Thalassemia: A Systematic Review to December 2012

New Synthetic Isoxazole Derivatives Acting as Potent Inducers of Fetal Hemoglobin in Erythroid Precursor Cells Isolated from β-Thalassemic Patients

Induction of fetal hemoglobin (HbF) is highly beneficial for patients carrying β-thalassemia, and novel HbF inducers are highly needed. Here, we describe a new class of promising HbF inducers characterized by an isoxazole chemical skeleton and obtained through modification of two natural molecules, geldanamycin and radicicol. After preliminary biological assays based on benzidine staining and RT-qPCR conducted on human erythroleukemic K562 cells, we employed erythroid precursors cells (ErPCs) isolated from β-thalassemic patients. ErPCs weretreated with appropriate concentrations of isoxazole derivatives. The accumulation of globin mRNAs was studied by RT-qPCR, and hemoglobin production by HPLC. We demonstrated the high efficacy of isozaxoles in inducing HbF. Most of these derivatives displayed an activity similar to that observed using known HbF inducers, such as hydroxyurea (HU) or rapamycin; some of the analyzed compounds were able to induce HbF with more efficiency than HU. All the compounds were active in reducing the excess of free α-globin in treated ErPCs. All the compounds displayed a lack of genotoxicity. These novel isoxazoles deserve further pre-clinical study aimed at verifying whether they are suitable for the development of therapeutic protocols for β-thalassemia.

The Long Scientific Journey of Sirolimus (Rapamycin): From the Soil of Easter Island (Rapa Nui) to Applied Research and Clinical Trials on β-Thalassemia and Other Hemoglobinopathies

In this review article, we present the fascinating story of rapamycin (sirolimus), a drug able to induce γ-globin gene expression and increased production of fetal hemoglobin (HbF) in erythroid cells, including primary erythroid precursor cells (ErPCs) isolated from β-thalassemia patients. For this reason, rapamycin is considered of great interest for the treatment of β-thalassemia. In fact, high levels of HbF are known to be highly beneficial for β-thalassemia patients. The story of rapamycin discovery began in 1964, with METEI, the Medical Expedition to Easter Island (Rapa Nui). During this expedition, samples of the soil from different parts of the island were collected and, from this material, an antibiotic-producing microorganism (Streptomyces hygroscopicus) was identified. Rapamycin was extracted from the mycelium with organic solvents, isolated, and demonstrated to be very active as an anti-bacterial and anti-fungal agent. Later, rapamycin was demonstrated to inhibit the in vitro cell growth of tumor cell lines. More importantly, rapamycin was found to be an immunosuppressive agent applicable to prevent kidney rejection after transplantation. More recently, rapamycin was found to be a potent inducer of HbF both in vitro using ErPCs isolated from β-thalassemia patients, in vivo using experimental mice, and in patients treated with this compound. These studies were the basis for proposing clinical trials on β-thalassemia patients.

Long-term safety and efficacy of hydroxyurea in patients with non-transfusion-dependent β-thalassemia: a comprehensive single-center experience

Over the past 20 years, hydroxyurea (HU) has emerged as an effective therapeutic agent in thalassemic patients to improve anemia and decrease the transfusion dependency. We evaluated long-term safety and clinical response to HU in patients with non-transfusion-dependent β-thalassemia (NTDT). In this retrospective study, medical records of 181 patients with NTDT were evaluated during October to December 2020 in Southern Iran. No requirement to blood transfusion was considered as sustained transfusion independence response. All patients were regularly examined and monitored for the occurrence of any adverse event (AE) of HU. The mean duration of HU consumption ± SD was 18.2 ± 4.0 (8-22) years. Overall, 149 patients (82.3%) had sustained transfusion independence response. β-globin gene mutations and XmnI polymorphisms were not significantly associated with clinical response (P > 0.05). Mild and transient AEs were reported in 60 patients (33%) with no requirement to drug interruption. Hydroxyurea with the dose of 8-15 mg/kg can be used as a safe and effective treatment in NTDT patients. It was well tolerated in long term without any serious complication or secondary malignancy. No relationship between XmnI or β-globin gene mutations with HU response was observed in this geographic area of the world.

β-Thalassemia Major and Coronavirus-19, Mortality and Morbidity: a Systematic Review Study

β-Thalassemia (β-thal) is one of the most common inherited diseases all over the world. These patients are very susceptible to infection disease, and the mortality and morbidity of infected patients will increase. The object of this systematic review study was to determine mortality and morbidity of infected β-thal patients with coronavirus disease 2019 (COVID-19). We searched PubMed, Elsevier, and Scholar Google to obtain related papers. The time of search was 21 June until 17 July 2020. All original and review articles and case reports were searched with key words: COVID 19, beta or β-thalassemia (β-thal), mortality and morbidity. Data were extracted after quality assessment of all articles. We obtained seven, 21 and six articles from PubMed, Scholar Google and Science Direct, respectively. Finally, seven articles were discussed in our study. The total number of enrolled patients was 34. Twenty-six patients carried transfusion-dependent β-thal major (β-TM). The most common symptoms were fever, cough, pain and dyspnea. Nine patients died. The result of this study has shown that the mortality and morbidity of infected β-thal patients will escalate.

Discovery of Novel Fetal Hemoglobin Inducers through Small Chemical Library Screening

The screening of chemical libraries based on cellular biosensors is a useful approach to identify new hits for novel therapeutic targets involved in rare genetic pathologies, such as β-thalassemia and sickle cell disease. In particular, pharmacologically mediated stimulation of human γ-globin gene expression, and increase of fetal hemoglobin (HbF) production, have been suggested as potential therapeutic strategies for these hemoglobinopathies. In this article, we screened a small chemical library, constituted of 150 compounds, using the cellular biosensor K562.GR, carrying enhanced green fluorescence protein (EGFP) and red fluorescence protein (RFP) genes under the control of the human γ-globin and β-globin gene promoters, respectively. Then the identified compounds were analyzed as HbF inducers on primary cell cultures, obtained from β-thalassemia patients, confirming their activity as HbF inducers, and suggesting these molecules as lead compounds for further chemical and biological investigations.

Thalidomide for Patients with β-Thalassemia: A Multicenter Experience

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.

The association of HBG2, BCL11A, and HBS1L-MYB polymorphisms to thalidomide response in Chinese β-thalassemia patients

Thalidomide has been shown to reactivate fetal hemoglobin (HbF) production and reduce the need for blood transfusions in β-thalassemia patients. However, some patients show a minor response or no response to thalidomide. In view of its potential side effects, targeted prescription of thalidomide is imperative. We initially aimed to explore the relevance of HBG2 (rs7482144), BCL11A (rs11886868, rs4671393, rs766432 and rs1427407) and HBS1L-MYB (rs9399137, rs4895440 and rs4895441) single nucleotide polymorphisms (SNPs) in thalidomide response. Eight SNPs were investigated by PCR and DNA sequencing, and their roles in thalidomide response in Chinese β-thalassemia patients were assessed. Results demonstrated that minor alleles of four SNPs were associated with an increased main response risk (rs7482144: P = 0.015; rs9399137: OR = 4.911, P = 0.029; rs4895440: OR = 4.522, P = 0.040; and rs4895441: OR = 4.522, P = 0.040). For patients with non-transfusion-dependent thalassemia (NTDT), with an increase in the minor allele numbers of rs7482144 (P = 0.011), rs9399137 (P = 0.013), rs4895440 (P = 0.011) and rs4895441 (P = 0.011), Hb increments after treatment were increased significantly as well. The cumulative effects of patients carrying any combination of one or three significant minor alleles included a gradually increased main response risk compared to those without the significant minor alleles (P = 0.040-0.018, OR = 8.556-11.000). Furthermore, Hb increments after treatment correlated with cumulative numbers of minor alleles in the four significant SNPs among patients with NTDT (P = 0.001). It was demonstrated that SNPs in HBG2 and HBS1L-MYB contributed significantly to thalidomide response in Chinese patients with β-thalassemia and that the cumulative number of minor SNP alleles may serve as good predictors of treatment response in this population.

Promising Response to Thalidomide in Symptomatic β-Thalassemia

Over the past decade, few reports suggested that the drug thalidomide (HbF inducer) may be of value in a subset of transfusion-dependent and non-transfusion dependent thalassemia patients. A cohort of 37 patients with symptomatic β-thalassemia syndrome [14 transfusions dependent thalassemia (TDT), and 23 Non-transfusion dependent Thalassemia (NTDT)], who were unable to pursue conventional therapy with transfusion and chelation, were recruited over 3 years in a center in Iraqi Kurdistan. After taking informed consent, patients were put on low dose Thalidomide (2-10 mg/kg), with regular follow up after that for a minimum of 8 months for a response. Patients with TDT were considered responders if their yearly transfusion requirement dropped by 25% or more, while NTDT responders were those who had a hemoglobin raise of 1 g m/dL or more. The median age of enrolled patients was 10 years (range 3-43) and included 21 males and 16 females. After a mean of 1.7 months (SD 0.76), responses were documented in 28 patients (75.7%). Among NTDT patients, a significant increase in hemoglobin from a mean of 7.83 (SD 1.07) to 9.96 g/dL (SD 1.11 g m/dL) was documented. While among TDT patients, there was a significant drop in yearly transfusions from 27 (SD 17.7) to 7.79 (SD 7.5) blood unit per year. The response in both categories was sustained after a median follow up of 15 months (8-36 m). Only minimal side effects were documented throughout in the form of constipation and only one patient developed extramedullary hemopoietic abdominal masses. A significant response to thalidomide was documented in the majority of TDT and NTDT patients, a response which was obtained after a mean of 1.7 months, and the response was sustained with limited side effects. The results support a possible role for this medication in a subset of thalassemia patients.

Clinical trial on the effects of thalidomide on hemoglobin synthesis in patients with moderate thalassemia intermedia

To investigate the efficacy and safety of thalidomide in patients with thalassemia intermedia (TI). Patients with a confirmed diagnosis of TI who met the trial criteria and signed consent forms were prescribed oral thalidomide 50 mg qn for 3 months from February 2017. Complete blood counts, Hb analysis, and liver and kidney functions were monitored monthly during treatment and any differences were compared before and after treatment. Patients with Hb increments > 2.0 g/dL were termed main responders (MaR), and those with Hb increments between 1.0 and 2.0 g/dL as minor responders (MiR), otherwise they were termed non-responders. Relevance analysis was performed to explore parameters predicting Hb increments after treatment. Adverse effects during treatment were carefully recorded. The overall response rate (ORR = MaR + MiR) and MaR rates were 78.6 and 50% after 1 month of treatment, respectively, and 85.7 and 71.4% after 3 months treatment. At the end of the treatment period, Hb and HbF increased by 2.5 ± 1.8 g/dL and 2.5 ± 1.6 g/dL, while bilirubin, lactate dehydrogenase, and the nucleated red blood cell count (NRBC) were significantly decreased, while the reticulocyte count significantly increased. Correlation analysis showed that the Hb increments correlated significantly with the ratio of HbF before treatment (r = 0.683, P = 0.007) rather than age, Hb, reticulocyte count, and NRBC before treatment. Adverse events during treatment were mild, and drug reduction or withdrawal from the trial was not required. Thalidomide had rapid and significant effects in patients with TI, and also, it is safe and convenient. But larger scale clinical trials will be required to confirm our conclusions.

TRIAL REGISTRATION

NCT02995707, https://www.clinicaltrials.gov/ct2/show/NCT03184844?term=thalidomide+thalassemia&rank=1 .

Hydroxyurea responses in clinically varied beta, HbE-beta thalassaemia and sickle cell anaemia patients of Eastern India

The haematological and clinical response to hydroxyurea was estimated in HbE-beta, beta thalassaemia and sickle cell anaemia patients of Eastern India, with variable clinical severity and transfusion requirement to determine whether hydroxyurea can help these patients to maintain their steady haemoglobin level without blood transfusions. Three hundred patients (189 HbE-beta thalassaemia, 95 beta thalassaemia and 16 other haemoglobinopathies including sickle cell anaemia) were selected for hydroxyurea therapy and were followed up for 48-60 months. Results suggest significant response to hydroxyurea therapy in 19 beta and 99 HbE-beta patients in the transfusion-dependent group (GR-I). All of them became transfusion-independent while on hydroxyurea therapy. The majority of responding patients were IVS1-5(G-C) in one of their alleles in HbE-beta cases (83 out of 119). Though IVS1-5(G-C) was found to be the commonest mutation in our selected patients, the mutational background of the patients does not found to have any significant correlation with the response category towards hydroxyurea as per the results observed in our study. But, the drug works pretty well in most of the transfusion-dependent patients, as these patients were withdrawn from regular blood transfusion. At the same time, partial or no response to the drug hydroxyurea was also recorded in our study.

Thalidomide has a significant effect in patients with thalassemia intermedia

OBJECTIVE

To investigate the effect of thalidomide in patients with thalassemia intermedia.

METHODS

We observed the effect of thalidomide in seven patients with thalassemia intermedia requiring blood transfusion. Four of the patients were transfusion-independent, and three patients were transfusion-dependent.

RESULTS

For the four transfusion-independent patients, hemoglobin concentration increased significantly (≥2 g/dl) in three and moderately (1-2 g/dl) in one. After 3 months of treatment, hemoglobin concentration increased 3.2 ± 1.2 g/dl compared to pretreatment. Among the three transfusion-dependent patients, transfusion was terminated after one month of treatment in one patient and decreased >50% in the other two patients, accompanied by an increase in the average hemoglobin concentration.

CONCLUSION

Thalidomide had a significant effect in patients with thalassemia intermedia. Further studies of a larger scale and more rigorous design are warranted.

Metallomic profiling to evaluate the response to drug treatment: hydroxyurea as a case study in β-thalassemia patients

Metallomic profiles of β-thalassemia patients after hydroxyurea treatment reveal a reduction in biometal dysregulations.

Radix Astragali Stimulates p38 MARK Phosphorylation in Pediatric Patients with β-Thalassemia

A previous study conducted by our group demonstrated that Radix Astragali compounded with Codonopsis pilosula and Plastrum testudinis was effective in treating pediatric β-thalassemia in a randomized, controlled clinical trial. However, the mechanism of action that underpins this treatment remains to be elucidated. Blood was collected from patients participating in this clinical trial and nucleated red blood cell-enriched mononuclear cells were isolated to facilitate the extraction of RNA and protein. RT-PCR was used to monitor the expression of globin genes and p38 MAPK, and total and phosphorylated p38 MAPK expression was assessed using Western blot analysis. Expression of α-, β-, and Aγ-globin mRNAs was not significantly affected following treatment with R. Astragali or the compounded formulation. However, Gγ-globin mRNA levels increased significantly in both treatment groups (when compared with pretreatment levels) following 12 weeks of treatment. Moreover, posttreatment Gγ-globin expression was significantly higher in both treatment groups compared with the control group. Although neither p38 MAPK mRNA nor protein levels were affected by the treatments, posttreatment phosphorylation of p38 MAPK was significantly increased in the R. Astragali and compounded formulation groups compared with the control group. These data suggest that the molecular mechanisms that underpin the efficacious use of R. Astragali (and its compounded formulation) in pediatric β-thalassemia treatment facilitate the induction of Gγ-globin expression following activation of p38 MAPK.

Hydroxyurea for reducing blood transfusion in non-transfusion dependent beta thalassaemias

BACKGROUND

Non-transfusion dependent beta thalassaemia is a subset of inherited haemoglobin disorders characterised by reduced production of the beta globin chain of the haemoglobin molecule leading to anaemia of varying severity. Although blood transfusion is not a necessity for survival, it is required when episodes of chronic anaemia occur. This chronic anaemia can impair growth and affect quality of life. People with non-transfusion dependent beta thalassaemia suffer from iron overload due to their body's increased capability of absorbing iron from food sources. Iron overload becomes more pronounced in those requiring blood transfusion. People with a higher foetal haemoglobin level have been found to require fewer blood transfusions. Hydroxyurea has been used to increase foetal haemoglobin level; however, its efficacy in reducing transfusion, chronic anaemia complications and its safety need to be established.

OBJECTIVES

To assess the effectiveness, safety and appropriate dose regimen of hydroxyurea in people with non-transfusion dependent beta thalassaemia (haemoglobin E combined with beta thalassaemia and beta thalassaemia intermedia).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of relevant journals. We also searched ongoing trials registries and the reference lists of relevant articles and reviews.Date of last search: 30 April 2016.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of hydroxyurea in people with non-transfusion dependent beta thalassaemia comparing hydroxyurea with placebo or standard treatment or comparing different doses of hydroxyurea.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the inclusion criteria in order to select trials for inclusion. Both authors assessed the risk of bias of trials and extracted the data. A third author verified these assessments.

MAIN RESULTS

No trials comparing hydroxyurea with placebo or standard care were found. However, we included one randomised controlled trial (n = 61) comparing 20 mg/kg/day with 10 mg/kg/day of hydroxyurea for 24 weeks.Both haemoglobin and foetal haemoglobin levels were lower at 24 weeks in the 20 mg group compared with the 10 mg group, mean difference -2.39 (95% confidence interval - 2.8 to -1.98) and mean difference -1.5 (95% confidence interval -1.83 to -1.17), respectively. Major adverse effects were significantly more common in the 20 mg group, for neutropenia risk ratio 9.93 (95% confidence interval 1.34 to 73.97) and for thrombocytopenia risk ratio 3.68 (95% confidence interval 1.13 to 12.07). No difference was reported for minor adverse effects (gastrointestinal disturbances and raised liver enzymes). The effect of hydroxyurea on transfusion frequency was not reported.The overall quality for the outcomes reported was graded as very low mainly because the outcomes were derived from only one small study with an unclear method of allocation concealment.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials to show whether hydroxyurea has any effect compared with controls on the need for blood transfusion. Administration of 10 mg/kg/day compared to 20 mg/kg/day of hydroxyurea resulted in higher haemoglobin levels and seems safer with fewer adverse effects. It has not been reported whether hydroxyurea is capable of reducing the need for blood transfusion. Large well-designed randomised controlled trials with sufficient duration of follow up are recommended.

Cell signaling pathways involved in drug-mediated fetal hemoglobin induction: Strategies to treat sickle cell disease

The developmental regulation of globin gene expression has shaped research efforts to establish therapeutic modalities for individuals affected with sickle cell disease and β-thalassemia. Fetal hemoglobin has been shown to block sickle hemoglobin S polymerization to improve symptoms of sickle cell disease; moreover, fetal hemoglobin functions to replace inadequate hemoglobin A synthesis in β-thalassemia thus serving as an effective therapeutic target. In the perinatal period, fetal hemoglobin is synthesized at high levels followed by a decline to adult levels by one year of age. It is known that naturally occurring mutations in the γ-globin gene promoters and distant cis-acting transcription factors produce persistent fetal hemoglobin synthesis after birth to ameliorate clinical symptoms. Major repressor proteins that silence γ-globin during development have been targeted for gene therapy in β-hemoglobinopathies patients. In parallel effort, several classes of pharmacological agents that induce fetal hemoglobin expression through molecular and cell signaling mechanisms have been identified. Herein, we reviewed the progress made in the discovery of signaling molecules targeted by pharmacologic agents that enhance γ-globin expression and have the potential for future drug development to treat the β-hemoglobinopathies.