Iron is essential for all human cells as well as neoplastic cells and invading microbes. Natural and synthetic iron chelators could affect biological processes involving iron and other metal ions in health and disease states. Iron overload is the most common metal toxicity condition worldwide. There are currently two iron chelating drugs, which are mostly used for the treatment of thalassaemia and other conditions of transfusional iron overload. Deferoxamine was until recently the only approved iron chelating drug, which is effective but very expensive and administered parenterally resulting in low compliance. Deferiprone (L1 or 1,2-dimethyl-3-hydroxypyrid-4-one) is the world's first and only orally active iron chelating drug, which is effective and inexpensive to synthesise thus increasing the prospects of making it available to most thalassaemia patients in third world countries who are not currently receiving any form of chelation therapy. Deferiprone has equivalent iron removal efficacy and comparable toxicity to deferoxamine. There are at least four other known iron chelators, which are currently being developed. Even if successful, these are not expected to become available for clinical use in the next five years and to be as inexpensive as deferiprone. The variation in the chemical, biological, pharmacological, toxicological and other properties of the chelating drugs and experimental chelators provide evidence of the difference in the mode of action of chelators and the need to identify and select molecular structures and substituents based on structure/activity correlations for specific pharmacological activity. Such information may increase the prospects of designing new chelating drugs, which could be targeted and act on different tissues, organs, proteins and iron pools that play important role not only in the treatment of iron overload but also in other diseases of iron and other metal imbalace and toxicity including free radical damage. Chelating drugs could also be designed, which could modify the enzymatic activity of iron and other metal containing enzymes, some of which play a key role in many diseases such as cancer, inflammation and atherosclerosis. Other applications of iron chelating drugs could involve the detoxification of toxic metals with similar metabolic pathways to iron such as Al, Cu, Ga, In, U and Pu.

MA received travel grants to attend scientific meetings from Apopharma and Novartis. PT has received travel grants to attend scientific meetings and honoraria for lectures and advisory work from Apopharma and Novartis. asparaginase). But the overall outcomes (5-year survival 36~54%) were clearly inferior to those seen for a contemporaneous sample of patients treated for standard ALL (5-year survival 84.6% in children).With a similar clinical poor prognosis to Ph + ALL, 1,7 patients with BAL present with high WBC counts and expression of CD10, high extramedullary infiltration, and low rate of long-term survival. This leads us to think that BAL and Ph + ALL perhaps have the same clinical entity, and that this could be why BAL patients adapt to the treatment of ALL or ALL-based approach. We agree with the authors that multi-center cooperative studies should be carried out in both clinical and basic research to further characterize the features of BAL.We conclude that MPO perhaps does not confer a good prognostic value in BAL patients as in AML patients. Intention-to-treat analysis showed that treatment with ALL or ALL-based approach, not AML protocol, resulted in high induction CR rates in BAL patients, but the longterm survival was still dismal.

Thalassemia is endemic in Cyprus with a frequency of 1 in 6 persons being a heterozygote and about 1 in 1,000 a homozygous thalassemia major patient. Cyprus has been a pioneer nation in reducing and almost eliminating the number of births of thalassemia major patients by introducing prenatal and antenatal diagnosis. The risks associated with bone marrow transplantation (BMT) make transfusion and chelation therapy the major form of treatment for the vast majority of thalassemia patients. Improved transfusion techniques, diagnostic methods, iron chelation and supportive therapy have increased the quality of life and survival of patients, some of whom are exceeding 50 years of age. The introduction of effective chelation therapy protocols using primarily deferiprone (L1) in combination with deferoxamine (DFO) resulted in the reduction of iron overload induced cardiac failures, which is the main cause of death in thalassemia major. Despite their chronic condition and tedious clinical management many patients are successful professionals, married and have children. The advancement in treatment is transforming thalassemia from a fatal to a chronic condition and some families are opting for giving birth to a thalassemic child rather than abortion.

Tissue damage caused by oxidative stress is a common characteristic of many conditions involving different major organs such as the brain, heart, liver and kidneys. The treatment of such conditions using classical antioxidants is not in most cases sufficient or effective because it lacks specificity and has a low therapeutic index. Increased evidence from in vitro, in vivo and clinical studies suggest that deferiprone (L1) can be used as a potent pharmaceutical antioxidant by mobilizing labile iron and copper and/or inhibiting their catalytic activity in the formation of free radicals and oxidative stress in tissue damage. The high therapeutic index, tissue penetration, rapid iron binding and clearance of the iron complex, and the low toxicity of L1, support its application as an antioxidant pharmaceutical for adjuvant, alternative or main therapy, especially in conditions where other treatments have failed. Substantial clinical improvement and reversal in most cases of the tissue damage has been observed in cardiomyopathy in thalassemia, diabetic nephropathy and glomerulonephritis in kidney disease, Friedreich's Ataxia and Fanconi Anemia patients. In contrast to L1, both deferoxamine (DFO) and deferasirox (DFRA) have major disadvantages in their use in non iron loading conditions due to toxicity implications. Further studies in the above and other conditions and optimization of the L1 therapy in each individual will increase the prospects of the application and role of L1 as a universal antioxidant pharmaceutical.

Excess cardiac iron deposition leads to congestive cardiac failure and accounts for more than 70% of deaths in thalassemia major patients. In three separate studies involving 145 thalassemia patients, serum ferritin and magnetic resonance imaging (MRI) relaxation times T2 and T2* have been compared for assessing iron load levels during chelation treatment. In two studies, variable levels of cardiac iron load have been detected by T2 and T2* in patients treated with deferoxamine (DFO), which, however, were unrelated to serum ferritin. In most cases, similar range levels from normal to severe cardiac iron load could be identified by both the T2 and T2* methods. However, in a few cases there were substantial differences in the levels detected between the two methods. In the third study, the ferrikinetics of the normalization of the iron stores during the International Committee on Chelation (ICOC) deferiprone (L1)/DFO combination protocol was followed up using T2 and T2* and serum ferritin. Iron deposits were found not to be proportionally distributed between the liver and the heart or uniformly distributed within each organ. Iron mobilization in each patient varied and iron deposits in each organ were cleared at different rates. Despite some limitations, the application of the MRI relaxation times T2 and T2* offers the best diagnostic methods for iron overload estimations in most organs and especially the heart. These MRI methods and serum ferritin could also be used for the ferrikinetics of iron mobilization and removal during chelation therapy and the normalization of the iron stores during the ICOC L1/DFO combination protocol. There is a need to standardize the two MRI relaxation times T2 and T2* methods and identify the factors causing the differences between them.