Hydroxyurea is not a cure for sickle cell disease

Recently, a Ugandan daily newspaper carried a headline that a cure for sickle cell disease had been found.

This gave a lot of hope to many people who are suffering from, and those who have children with the disease. I personally received a number of phone calls and emails; my Facebook wall was filled with messages informing me of a sickle cell medical breakthrough, while others were congratulating me.

My friend, a mother to a son with sickle cell disease, also got numerous calls. Her friends and relatives were asking her to take Isiah to Mulago to be cured of the disease. The media report was in reference to a clinical trial for Hydroxyurea, a cancer drug that is also used to treat sickle cell disease in USA and Europe.

The trial is expected to start in Mulago next month, with 200 patients between 12 months and 47 months taking part. To many, it seemed as if the drug was new in Uganda, and it was going to eliminate sickle cell. Hydroxyurea is not a cure and has been in Uganda for some time. My first interaction with it was in 2011, when a doctor prescribed it. It was difficult to get it in pharmacies, but these days it’s common everywhere.

Hydroxyurea was first synthesised in 1869 in Germany, by Dresler and Stein. It started as an anti-cancer drug. Today, it has gained wide acceptance among haematologists as the number one medication for sickle cell disorder. This drug works by kick-starting, within the bone marrow, the production of potent blood cells that all babies are born with, the foetal haemoglobin (or HbF).

By the time a baby reaches the age of six months, HbF has been all but depleted and replaced with adult haemoglobin (HbA). This is why, in most cases, prior to the first six months of life, babies with sickle cell disease rarely exhibit symptoms of the disorder. HbF suppresses sickling.

Researchers credit Hydroxyurea for the improved life expectancy and the quality of life of people with sickle cell disease. For example, in the United States, the average life expectancy was 14 years in 1973, but it is now topping 50s. The US Food and Drug Authority approved Hydroxyurea for use by adults with sickle cell in 1998. And for the past couple of years, evidence has emerged, confirming its effectiveness in babies and children.

But with its effectiveness and efficacy in Europe and the US, it has not been studied in Uganda or any other malaria-endemic country, not even Nigeria where it has been used for a longer time. I hope this clinical trial is going to help us discover the good and bad of the drug in sub-Saharan Africa. With evidence from a number of people I have interacted with, the drug has had both positive and negative effects.

In June this year, on one of Sickle Cell Network Uganda’s community awareness outreaches in Bamunanika in Luweero, we met a 23-year-old woman who became paralysed after taking Hydroxyurea. She stopped talking and became mentally ill. She had only started to recover when her parents stopped giving her Hydroxyurea. But even then, her talking was uncoordinated.

So, despite its applicability, Hydroxyurea does not work for everyone. David Nathan of Dana Farber Cancer Institute, USA, says that Hydroxyurea works in only 50 per cent of patients. Similarly, for obscure reasons, Hydroxyurea does not address every sickle cell complication. In the same vein, although higher HbF levels are associated with less frequent acute pain episodes and reduced disease severity, they seem to have a weak impact on priapism, stroke, pulmonary hypertension and blood vessel complications.

Professor Graham Serjeant, a sickle cell specialist, argues that although many doctors say Hydroxyurea has changed the lives of many patients, some do not respond at all. He says there are toxic effects and “we don’t know about long term dangers”.

Therefore, we should take note that Hydroxyurea is not a cure drug for sickle cell disease. I urge those who are carrying out the trial to provide full information, including the benefits and likely side effects, to help participants make informed decisions. It should also be important to follow up on those people who have used Hydroxyurea before