WHAT IS IRON CHELATION THERAPY?

Regular blood transfusions are the main treatment for patients with hereditary haemoglobinopathies, but they entail a major drawback: any blood that is transfused into the patient carries with it an amount of iron that the human body can’t get rid of on its own. Over the course of time, this tends to build up, especially in the liver, heart and endocrine organs. This gradual iron overload causes very severe disorders in thalassaemic patients, and these can be lethal if they remain untreated.

Blood transfusions therefore need to be combined with drug therapy to trap the excess iron and remove it from the body. These drugs are known as iron chelators – they grasp onto iron atoms like a pair of microscopic claws and then excrete them in the urine. Iron chelation therapy is therefore absolutely essential for thalassaemic patients.

Until a few years ago, the only commercially available iron chelator was deferoxamine. This drug, however, has one major limitation: it needs to be taken 5 to 7 days a week, and infusion times are very long, from 8 to 12 hours a day. The treatment is complex, tiring and hard to follow consistently. In addition, deferoxamine is harmful to some patients, leading to intolerance reactions and toxicity.

In order to overcome the difficulty of administering the drug and to offer alternative treatments, drugs such as deferiprone and deferasirox have been developed in recent years. These drugs can make iron chelation therapy much easier as they can be taken orally, in the form of syrup and tablets that can either be swallowed whole or dissolved in water. Deferiprone is also particularly good at reducing the iron load in the heart, a further beneficial effect for thalassaemia patients.

In addition to its undeniable positive effects, however, deferiprone may have side effects. Some of these effects – such as nausea, vomiting and diarrhoea, pain in the arms or legs – can be resolved either spontaneously or by discontinuing the drug, and pose no risk to the patient’s life; other side effects are more serious and may even endanger the patient’s life, such as a reduction in white blood cells and platelets, or liver and kidney disorders. A careful and rigorous study of the drug interactions with the body is therefore needed to ensure that patients can take it safely.

Deferiprone has been studied primarily in adult patients with thalassaemia, whereas there is little data available on its use in paediatric patients and in other hereditary anaemias. That is the gap which the DEEP (“DEferiprone Evaluation in Paediatrics”) project aims to fill.