Preliminary report: hydroxyurea produces significant clinical response in thalassemia intermedia

Hematologic and clinical responses of thalassemia intermedia patients to hydroxyurea during 6 years of therapy in Iran

Hydroxyurea (HU) is a well-known chemotherapeutic agent that has been used largely for the treatment of various myeloproliferative conditions over the past 20 years. In beta-thalassemia, the role for HU is much less clear and remains controversial. This study was undertaken to describe the hematologic and clinical responses of thalassemia intermedia patients to HU treatment during 6 years in Southern Iran. One hundred sixty-three thalassemia intermedia patients were selected among the 3,000 cases of beta-thalassemia in Southern Iran from 1998 to 2003. All patients underwent laboratory tests and quantitative hemoglobin electrophoresis. Group 1 comprised patients receiving regular blood transfusions (after age 2 years old). Group 2 comprised those without any history of blood transfusions suffering from chronic anemia or long-interval transfusions. The state of energy, fatigability, and mood were recorded before the trial. Facial change was compared before and after treatment with HU. Electrocardiogram and echocardiography were carried out before and during treatment with HU. All patients were treated with HU; the starting dose was 8 to 12 mg/kg/d given orally once a day. Of the 163 patients, 149 tolerated the HU well and showed a dramatic response to the drug. Eighty-three of 106 transfusion-dependent patients (group 1) became completely transfusion-free, and 23 had one or two transfusions throughout the study. Sixteen of 43 patients (group 2) who were on long-interval transfusions became transfusion-free and 27 group 2 patients were transfusion-free, with developing acceptable hemoglobin levels. After treatment, 97% of patients described an increase in exercise tolerance, and no significant facial change was observed after therapy. No change in spleen size was observed in 83% of the patients. HU therapy was also associated with a marked increase in hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin. HU may be administered in thalassemia intermedia patients to minimize or even obviate the need for regular transfusions and concomitant iron overload, and HU therapy appears to be safe and effective when administered in thalassemic patients.

Hydroxyurea in thalassemia intermedia—a promising therapy

Pharmacological agents such as hydroxyurea (HU) have been known to cause induction of fetal hemoglobin and possibly may alleviate the symptoms in thalassemia intermedia patients. Thirty-seven patients with beta-thalassemia intermedia were enrolled to assess response to HU therapy. Major response was defined as transfusion independence or hemoglobin rise of more than 20 g/l and minor response as rise in hemoglobin of 10-20 g/l or reduction in transfusion frequency by 50%. The median age was 10 years (range: 4-50 years) and median follow-up was 12 months (range: 4-36 months). Twenty-six patients (70.2%) showed response to HU therapy. Seventeen patients (45.9%) were major responders, and nine patients (24.3%) showed minor response. There was no correlation of response with beta-thalassemia mutation or XmnI polymorphism; however, the presence of alpha(3.7) deletion was associated with major response in three patients. Mean fetal hemoglobin (HbF) levels rose on HU therapy. Older age, low baseline F cell percent, and low baseline HbF levels (below 10%) were predictors of poor response. Response was evident within 1 month of starting HU therapy in the majority of responders. Thus, a short trial of HU therapy can predict durable response.

The role of fetal hemoglobin–enhancing agents in thalassemia

Augmentation of fetal hemoglobin (HbF) synthesis can reduce the severity of beta-thalassemia by improving the imbalance between alpha- and non-alpha-globin chains. However, previous clinical trials of pharmacologic induction of HbF in thalassemia produced inconsistent results. Striking responses in HbF and total hemoglobin synthesis were occasionally observed, but in most patients, the increase in gamma-globin synthesis was inadequate to influence the clinical course of thalassemia. A small number of patients treated with azacytidine demonstrated a consistent response, but the development of this drug was abandoned due to concerns over toxicity. Decitabine, an analog of azacytidine, is a more potent inhibitor of DNA methyltransferase, and may be less toxic in clinical use. Trials in sickle cell anemia have confirmed that decitabine is effective in patients refractory to hydroxyurea. The clinical trials of decitabine in thalassemia must carefully evaluate the dose and route of administration, and address concerns about long-term side effects.

Long-term hydroxyurea therapy in beta-thalassaemia patients

OBJECTIVE

The study aimed to investigate the use of hydroxyurea (HU) for the treatment of beta-thalassaemia (beta-thal) patients.

METHODS

We examined the haematological effects of orally administered HU (10-20 mg/kg/d) in 11 patients, including four beta-thal major and seven beta-thal intermedia patients. Complete blood count and levels of foetal haemoglobin (HbF), liver enzymes and serum creatinine were evaluated before and during HU. Response to therapy was evaluated at 6 months of treatment.

RESULTS

A substantial increase in haemoglobin (Hb) level (4.1 g/dL), leading to complete withdrawal from a regular transfusion programme, was observed in one unique beta-thal major patient. In the beta-thal intermedia patients, increases in Hb level of 1.3, 1.9 and 2.0 g/dL were observed in three of seven (42.9%) patients during HU therapy. The mean values of Hb, mean corpuscular haemoglobin (MCH), and HbF were higher during HU treatment than baseline values (8.7 vs. 7.7 g/dL, P = 0.05; 26.7 vs. 22.9 pg, P = 0.05; 57.2 vs. 44.9%, P = 0.04; respectively). In contrast, the mean reticulocyte count measured during therapy decreased (97.0 x 10(9) vs. 632.0 x 10(9)/L, P = 0.03). No correlations were observed between levels of Hb and HbF (r = 0.77, P = 0.10), and levels of Hb and reticulocyte counts (r = 0.26, P = 0.31). No significant toxicity was observed in our patients.

CONCLUSION

These results suggest that HU may improve Hb levels in beta-thal. Thus, we may conclude that a large trial concerning the response to HU in these patients should be carried out to clarify this issue.

Use of hydroxyurea and recombinant erythropoietin in management of homozygous beta0 thalassemia

This report describes the sustained response of an Iranian girl with homozygous beta(0) thalassemia (IVS-II-1G-->A) to hydroxyurea (HU) and recombinant erythropoietin (rEPO). Since the start of this regimen 7 years ago, she has been transfusion-independent and her hemoglobin is maintained between 9.5-11.0 gm/dL. She is maintaining consistent growth around the 10th percentile for age and enjoys a good quality of life. She has not had any therapy-related adverse effects. This experience suggests that therapy with HU and rEPO may be useful long-term in some patients with beta thalassemia.