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Knowledge Centre - Care of Thalassaemics - Chelation Therapy

What is Iron Overload

Packed Cells that are transfused to the patient contain Haemoglobin, which contain iron. Repeated blood transfusion result in more and more iron being deposited in the blood stream. Beyond a point this iron becomes undesirable, and gets deposited in the heart, pancreas, liver, spleen, pituitary glands, thyroid and parathyroid glands. This could lead to cardiac problems, diabetes, cirrhosis of the liver, growth retardation, delayed puberty, bacterial infections, osteoporosis etc. The life expectancy of a Thalassaemia Major child depends on the ability to control the iron overload.

How is Iron Overload monitored?

The most common method of monitoring iron overload is by checking the Serum Ferritin level, which is measured in terms of nanograms per milliliter (ng/ml). A Serum Ferritin level of above 1000 ng/ml signifies iron overload, which is when iron chelation therapy is started. However the monitoring by Serum Ferritin levels has certain limitation with respect to its interpretation. But easy accessibility and lower costs makes this method the most common choice. Comparing the Serum Ferritin levels of a patient from one period to another gives a good indication of the changes in the iron overload.

The best method for measuring iron levels is Liver Biopsy. Apart from being very costly, it is not preferred due to its invasive nature, which could cause internal bleeding.

The other methods of monitoring iron overload are SQUID (Superconducting Quantum Interference Device) and MRI (Magnetic Resonance Imaging).

Iron Chelation

The process of removal of iron from the blood stream is called as ‘Iron Chelation’. This is started when the child is approximately 2 years old after checking the Serum Ferritin levels. The aim of iron chelation is to keep the Serum Ferritin levels in the range 1000 to 1500 ng/ml. The different drugs that are available for iron chelation are:

  1. Desferrioxamine (DFO)
    Desferrioxamine is a compound which binds with iron and disposes it off mainly through the stool and partly through urine. It cannot be administered orally, and is given subcutaneously by a slow infusion pump. The daily dose of 30-50 mg/kg of patient’s body weight is given daily over a period of 8 to 10 hours. DFO contributes significantly in controlling iron overload in the heart, liver and endocrine glands. DFO is better known as ‘Desferal’, the brand name under which is made available by Novartis. Desferal is time tested and therefore considered more dependable by those who can afford it. However, due to the slow, subcutaneous infusion compliance to the therapy is a problem.
  2. Deferiprone
    Deferiprone is the first oral drug to be developed for iron chelation. It is better known as Kelfer - the brand name under which it is made available by CIPLA in India. The recommended dose is 50 to 100 mg/kg of patient’s body weight. Kelfer has been known to work better with iron overload in the heart. However some children show symptoms of nausea, vomiting, abdominal pains, diarrhoea and joint pains. Patients using this therapy must get blood tests and physical examination of joints done regularly.
  3. ICL 670
    ICL 670 is the latest oral chelator to be developed. It is known to be twice as efficacious as Desferal. Initially introduced by NOVARTIS in Europe as ‘Exjade’ and later in India as ‘Asunra’, the drug is now also made available by CIPLA as ‘Desirox’. The excretion of iron is mainly through faecal matter. The maximum dose recommended is 30 mg/kg of patient’s body weight.

Initially Desferal seemed to be the only option available. The compliance problem and the prohibitive cost seemed to be the hurdle in its use. Kelfer was increasingly used in India due to ease of administering and low cost. However after studies indicated that Kelfer worked better than Desferal with respect to removal of cardiac iron overload, doctors started suggesting a combination therapy of Desferal and Kelfer. With reports of successful trials many patients would like to watch its efficacy on Indian patients before switching over to Asunra or Desirox. It is believed that over time, ICL 670 (either Asunra or Desirox) will become the preferred iron chelator.