Promising Response to Thalidomide in Symptomatic β-Thalassemia

Thalidomide and Hydroxyurea in Transfusion-Dependent Thalassemia: Efficacy, Safety Profile and Impact on Quality of Life

Transfusion-dependent thalassemia (TDT) is a major public health concern in India, requiring regular transfusions for survival. There is also significant morbidity caused by iron overload and transfusion related infections. Novel therapies targeting fetal hemoglobin induction are the need of the hour in resource-poor institutions for patients where transplant is not feasible for various reasons. This single arm, non-randomised prospective trial evaluated the efficacy and safety of a combination of low dose thalidomide and hydroxyurea in TDT along with the impact on quality of life (QoL). It included 41 TDT patients, who failed a reasonable trial of hydroxyurea. Complete response (CR) was defined as transfusion independence and partial response (PR) denoted at least a 50% reduction in transfusion requirement. The rest were defined as non-responders (NR). The mean age of the cohort was 20.78 years (range 12-45 years). There were 13 males and 28 females. Nineteen (46.3%), 7 (17.1%), and 15 (36.6%) patients achieved CR, PR, and no response respectively. The overall response rate (CR + PR) was 63.4%. There was a significant increase in hemoglobin levels with decrement in transfusion burden and ferritin levels. There were no significant adverse reactions. No significant predictors of response were found including amongst genetic modifiers. It improved the health related QoL amongst responders. The combination of thalidomide and hydroxyurea appear safe and effective in the reduction in transfusion requirement of TDT patients. The judicious use of these drugs can improve the quality of life and pave the way for patients not eligible for a stem cell transplant.

Clinical efficacy of thalidomide for various genotypes of beta thalassemia

OBJECTIVE

The objective of this study was to investigate the therapeutic efficacy of thalidomide across various genotype presentations of β-thalassemia so as to facilitate the early screening of thalidomide-sensitive thalassemia cases and to understand the impact of iron overload on thalidomide.

METHODS

From our initial sample of 52 patients, we observed 48 patients with β-thalassemia for two years after administration of thalidomide. This cohort included 34 patients with transfusion-dependent thalassemia (TDT) and 14 patients with non-transfusion-dependent thalassemia (NTDT). We recorded the values of hemoglobin (Hb), fetal hemoglobin (HbF), and serum ferritin (SF) in the baseline period and at 1, 3, 6, 12, 18, and 24 months after enrollment, as well as the pre- and post-treatment blood transfusion volume in all 48 cases. According to the increase in Hb levels from baseline during the 6-month observation period, the response to thalidomide was divided into four levels: main response (MaR), minor response (MiR), slow response (SLR), and no response (NR). A decrease in serum ferritin levels compared to baseline was considered alleviation of iron overload. We calculated the overall response rate (ORR) as follows: ORR = MaR + MiR + SLR/number of observed cases.

RESULTS

The ORR was 91.7% (44/48 cases), and 72.9% showed MaR (35/48 cases). Among the 34 patients with TDT, 21 patients (61.8%) were free of blood transfusion, and the remaining 13 patients still required blood transfusion, but their total blood transfusion volume reduced by 31.3% when compared to the baseline. We found a total of 33 cases with 10 combinations of advantageous genes, which included 5 cases with βCD41-42/βCD17 and 6 cases with βCD41-42/β-28. Based on the treatment outcomes among the 48 cases in the observation group, there were 33 cases in the MaR group and 15 cases in the SLR/NR group. There was a difference in HbF between the two groups at baseline (P = 0.041). There were significant differences between the two groups in Hb and HbF at the time points of 6 and 12 months, respectively (P < 0.001). Compared to the baseline measurement, there was a significant decrease in the level of SF at months 12 and 24 (P < 0.001).

CONCLUSION

In this study, we identified 10 β-thalassemia gene combinations that were sensitive to thalidomide. These gene combinations can be used for initial screening and to predict the therapeutic effect of thalidomide in clinical practice. We examined the therapeutic response to thalidomide and found that the administration of thalidomide in combination with standardized iron removal was more beneficial in reducing iron overload.

Long-term clinical efficacy and safety of thalidomide in patients with transfusion-dependent β-thalassemia: results from Thal-Thalido study

Regular blood transfusion is the mainstay of treatment in transfusion-dependent β-thalassemia (TDT); however, transfusions culminate in an array of serious complications. Therefore, a single-arm, non-randomized clinical trial was conducted in hydroxyurea refractory TDT patients to explore the long-term safety and efficacy of thalidomide. The primary outcomes for efficacy were rise in hemoglobin (Hb) level and changes in transfusion frequency. Whereas, several clinical and laboratory parameters were assessed for safety of thalidomide. Secondary outcomes included changes in serum ferritin, serum lactate dehydrogenase (LDH), serum uric acid, red blood cell indices, and size of liver and spleen. A total of 532 patients were followed for a period of 30 months. Significant increase in mean Hb level was identified at 6 months (1.4 g/dL, p ≤ 0.001) and 30 months (2 g/dL, p ≤ 0.001) in comparison with baseline. A total of 408 (76.7%) patients responded to thalidomide therapy (excellent responders 25.8%, good responders 31%, and partial responders 19.9%) and attained transfusion independence within 6 months of therapy. A significant decline in mean ferritin, LDH level, liver size, and spleen size was observed. No unfavorable effects were observed on kidney and liver functions. Mild adverse events were reported in 48 (9%) patients and serious adverse events, including cerebral vascular accident and portal vein thrombosis were reported in two patients each. This study concludes that thalidomide is an effective and well-tolerated drug that can improve Hb levels and reduce transfusion burden in hydroxyurea refractory TDT patients.Trial registration: This trial is registered at http://www.clinicaltrial.gov as # NCT03651102.

Pharmacological Induction of Fetal Hemoglobin in β-Thalassemia and Sickle Cell Disease: An Updated Perspective

A significant amount of attention has recently been devoted to the mechanisms involved in hemoglobin (Hb) switching, as it has previously been established that the induction of fetal hemoglobin (HbF) production in significant amounts can reduce the severity of the clinical course in diseases such as β-thalassemia and sickle cell disease (SCD). While the induction of HbF using lentiviral and genome-editing strategies has been made possible, they present limitations. Meanwhile, progress in the use of pharmacologic agents for HbF induction and the identification of novel HbF-inducing strategies has been made possible as a result of a better understanding of γ-globin regulation. In this review, we will provide an update on all current pharmacological inducer agents of HbF in β-thalassemia and SCD in addition to the ongoing research into other novel, and potentially therapeutic, HbF-inducing agents.

Evaluation of the combination therapy of hydroxyurea and thalidomide in β-thalassemia

Transfusion-related complications and lack of resources in low-to-middle-income countries have led to a search for novel therapies to reduce the need for blood transfusions in patients with β-thalassemia. Hydroxyurea (HU) has demonstrated promising outcomes; additionally, thalidomide has also shown improvement in hemoglobin (Hb) levels for patients with β-thalassemia in some studies. This study presents the findings of a single-arm nonrandomized trial to evaluate the efficacy of combination therapy of HU and thalidomide in children with β-thalassemia. A total of 135 patients (median age, 6 [interquartile range, 3-10] years), 77 (57%) males and 58 (43%) females, were followed first using HU alone, for 6 months, and then using the combination of HU and thalidomide for another 6 months. The primary outcome was a response to therapy, as measured by the number of transfusions required and Hb levels, for patients while receiving HU alone and then while using the combination therapy. Study findings showed a significant decline in blood transfusion volume (P < .001) and a significant increase in median Hb levels within 3 and 6 months of the combination therapy (P < .001). Eighty-nine (65.93%) participants were good responders, 16 (11.85%) were responders, and 30 (22.22%) were nonresponders, whereas the responders had variable genetic mutations. A total of 38 adverse events were reported that resolved on supportive treatment or temporary hold of the intervention. The combination therapy demonstrated promising results and could be considered for a diverse patient population with β-thalassemia. This trial was registered at www.clinicaltrials.gov as #NCT05132270.

Investigating the Efficacy and Safety of Thalidomide for Treating Patients With ß-Thalassemia: A Meta-Analysis

At present, the main therapies for ß-thalassemia patients include regular blood transfusion and iron chelation, associating with a number of limitations. Thalidomide, a fetal hemoglobin (HbF) inducer that promotes γ-globin gene expression, has been reported to be effective for ß-thalassemia. Thus, this meta-analysis was conducted to assess the efficacy and safety of thalidomide for treating patients with ß-thalassemia. We searched the related studies from eight databases published from inception until December 1, 2021. The R 4.0.5 language programming was used to perform meta-analysis. After screening of retrieved articles, 12 articles were included that enrolled a total of 451 patients. The Cochrane Collaboration risk assessment tool was used to evaluate the quality and the bias risk of the randomized controlled trials (RCTs), and non randomized trials were assessed using Newcastle-Ottawa Scale (NOS). After treatment with thalidomide, the pooled overall response rate (ORR) was 85% (95% confidence interval (CI): 80–90%), and the pooled complete response rate (CRR) was 54% (95% confidence interval: 31–76%). Compared with the placebo group, the thalidomide group had higher odds of overall response rate (odds ratio = 20.4; 95% CI: 6.75–61.64) and complete response rate (odds ratio = 20.4; 95% CI: 6.75–61.64). A statistically significant increase in hemoglobin level and HbF level after treatment, while there was no statistically significant difference in adult hemoglobin (HbA) level, spleen size, and serum ferritin. According to the results of ORR and CRR, transfusion-dependent thalassemia (TDT) patients showed remarkable efficacy of thalidomide, 83 and 52% respectively. So we analyzed 30 transfusion-dependent thalassemia patients from three studies and found that the most frequent ß-globin gene mutations were CD41-42 (-TCTT), while response to thalidomide did not show any statistically significant relationship with XmnI polymorphism or CD41-42 (-TCTT) mutation. About 30% of patients experienced mild adverse effects of thalidomide. Collectively, thalidomide is a relatively safe and effective therapy to reduce the blood transfusion requirements and to increase Hb level in patients with ß-thalassemia.

Efficacy of Thalidomide Treatment in Children With Transfusion Dependent β-Thalassemia: A Retrospective Clinical Study

Background: Thalidomide has been reported as a promising treatment for reducing transfusion volume in adults with β-thalassemia. However, the evidence about the safety and efficacy of thalidomide on children with transfusion dependent β-thalassemia (TDT) is scarce.

Methods: Seventy-seven children with TDT treated with thalidomide at least for 6 months were included and retrospectively analyzed. Oral dose was started at 2.5 mg·kg-1·d-1. Blood volume for maintenance of hemoglobin above 90 g·L-1 compared with pre-treatment volume is the evaluation index for response.

Results: After the sixth month treatment, 51/77 (66.2%) maintained Hb over 90 g·L-1 without transfusion. Adverse events were reported in 48 (63.2%) patients. Age, sex, genotype category, dosage, and transfusion interval before thalidomide treatment were not correlated to treatment response. The AUC was 0.806 for the HbF at the third month of treatment in predicting probability of major responders at the sixth month treatment. Based on Youden’s index algorithm in the ROC curve, 47.298 g·L-1 was the optimal cut-off value of the HbF at the third month of treatment in predicting major responders at the sixth month treatment, with sensitivity of 67.5% and specificity of 93.3%.

Conclusions: The dose of thalidomide between 2.5 mg·kg-1·d-1 and 3.6 mg·kg-1·d-1 is effective in TDT children. Severe side effects are uncommon. HbF concentration of 47.298 g·L-1 at the third month is recommended as the predictor for further major responders.

Drug safety in thalassemia: lessons from the present and directions for the future

Introduction: Beta-thalassemia is an autosomal recessive hereditary anemia characterized by reduced or absent β-globin chain synthesis, affecting about 60,000 people peryear. Management for β-thalassemia major includes regular blood transfusions followed by iron chelating therapy and drug targeting ineffective erythropoiesis.Areas covered: The safety of licensed drugs for the management of β-thalassemia is reviewed, using evidence from clinical trials and observational research. Such drugs include the iron chelators and the erythrocyte maturation agent luspatercept. The safety of emerging treatment, such as hydroxyurea and thalidomide is also reviewed.Expert opinion: Beta-thalassemia is arare disease, and is not surprising that there are limited studies investigating the safety of drugs used in this disease. Indeed, although observational studies are the main source of drug safety information in areal-world setting, only eleven studies were identified for iron-chelators and none of these estimated the risk of agiven safety outcome. Future work should aim to better leverage existing sources of real-world datato investigate drug safety in thalassemia.

Experience with combination of hydroxyurea and low-dose thalidomide in transfusion-dependent beta thalassemia patients

Hydroxyurea (HU) and thalidomide have been reported to improve clinical and hematological parameters in transfusion-dependent beta thalassemia (TDT). Therefore, we retrospectively analyzed the combination of HU and thalidomide in 140 transplant ineligible TDT, ≥ 10 years old, visiting our thalassemia clinic between October 2014 and November 2019. Responses were defined as maintenance of hemoglobin ≥9gm/dl without transfusion as complete response (CR) and with at least 50% reduction in transfusion burden as partial response (PR). Patients with less than 50% transfusion burden reduction for consecutive 6 months of therapy were defined as non-responders (NR), and treatment was discontinued thereafter. Primary end point was overall response rate (ORR) at last follow-up. At median follow-up of 22.6 (95% CI 16.4-28.7) months, 76 (57.2%) patients achieved CR and 19 (14.3%) achieved PR, accounting to an ORR of 71.5%. Among responders at last follow-up, a significant increase in the post-treatment hemoglobin (0.88±0.37gm/dl, p<0.0001) and drop in serum ferritin (-1490.5ng/ml, p<0.0001) were observed. Median time to CR was 124 (95% CI 75.3-172.6) days. Median longest continuous CR was 791 (95% CI 662.2-919.7) days. Common toxicities observed were sedation (25%), hyperbilirubinemia {(23.57%, grade 3/4 =17 (12.14%)}, and constipation (22.8%). Nearly three-fourth of the patients has responded with majority having CR. Adverse events are a concern; hence, regular close monitoring is a prerequisite.