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SECTION 2
Thalassemia Major
Chapter 10
Questions about the Future
 
 


What hope is there for a better future for thalassemics?
         It is always difficult to see what will happen in the future, though we can make some reasonable guesses.
         Complications should become less and less frequent, and management should steadily improve, because our experience and understanding of the disease is steadily increasing.
         New drugs will probably make life more liveable. In particular, a lot of research being done to find a drug for treating iron overload, that can be taken by mouth.
         More Thalassemics will have a bone-marrow transplant, and it should become safer, and more widely available.
         It may become possible to replace the thalassemic gene with a normal gene by "Genetic Engineering" and so to cure the disease finally and completely.


What about the oral iron chelating agent - "the pill"?
         As of March 1990 patients at the Whittington and Royal free Hospitals in London are taking part in an experimental study of a new drug, 1,2 Dimethyl-3-hyrdroxprid-4-one, one of a family of drugs called alpha-keto-hydroxy-pyridones. The aim is to see if it works, and is safe. The patients have to take quite a large amount of drug everyday. It is taken in capsules (because it tastes bitter) two hours before a meal.
         The drug is a white powder that acts rather as Desferal does. It combines with iron in the body to make an orange compound, and brings it out in the urine. So, as with Desferal, the urine goes orange on days when people take the drug.
         So far, "the pill" seems to bring out as much iron as Desferal does, and the patients do not seem to have serious problems. As they can stop their Desferal infusions when they are taking the drug, thalassemics like being "Guinea Pigs" in this experiment.
         Some other centers are now joining in, and treating a selected group of patients.
 

 
Why can't we all have Alpha-keto-hydroxy-pyridone now?
         To be honest, it is never best to be the first patient on any new treatment. No drug that is effective is absolutely safe. They all have some side-effects, and we have to learn what they are before we can safely give it to patients. That is why there are rules that new drugs must be tested in a large number of animals, and be tried in many people under experimental conditions, before they are sold for general use.
         A new iron chelating agent must be particularly sage, because it will be taken in a large dose daily for life - which is rather exceptional where drugs are concerned. Therefore safety really does come first and this drug must be very carefully tested and studied by experts, in patients taking it over quite a long period, before being widely used.
         In addition, at present Dr Kontogheorges is making the drug himself, and he can only produce a limited amount.
         Fortunately a drug firm is now carrying out the necessary tests in animals. Once they have given satisfactory results, the firm will produce the drug to the approved standard of purity, for larger studies in people.


Can other patients join in the study?
         Patients from further away cannot join the study at present, because "test" patients need to be under constant surveillance by the research groups.


What has to be done to introduce a new drug?
         The diagram (Figure 17) shows the steps in developing a new drug. You can see that is bound to take a long time. 1,2 dimethyl-1-3-hydroxypyrid-4-one is now at the stage of acute tests in a few patients and long term animal tests are starting.


Is alpha-keto-hydroxy-pyridone the only possibility for getting a pill?
         Now this gets a bit complicated. In fact, the alpha-keto-hydroxypyridones are a group of closely-related drugs. Only one of the group, that Dr Kontogheorges thinks is the most promising, is being tested on thalassemic patients at present. But some other doctors think some different members of the same family of alpha-keto-hydroxypyridones are equally good, and may be safer, so they are working hard on them. This is an advantage, because if the one being studied now turns out to cause complications, there will be these other one to turn to. But it is also, in a sense, a disadvantage, because it makes it necessary to do longer preliminary studies in animals to make sure that we choose the best drug from this family from the beginning. This takes time, and causes some delays in deciding which drug to go ahead with.
         In addition, there are at least two other groups of promising compounds, that look very good in the laboratory and seem safe in animals. One, "PIH" (pyridoxal insonicotinic hydrazone) is being studied in Australia, Thailand and the United States. It has had acute animal trials, and has been tested in a few patients, but is not being manufactured.
         A third drug that seems to be effective and safe in animals has been developed in Israel and the United States, but has not yet been tried in Humans.
 

 
So can we be sure that there will be a "pill" in 2 or 3 years?
         No, you can never be sure of a thing until it has actually happened. But the tests are going quite well, and there is more than one possibility, so it looks very hopeful.


What about bone-marrow transplantation?
         As bone-marrow transplantation is used more often for thalassemia, it should gradually become safer.
         At present only young people with a full-compatible donor can have a bone-marrow transplant. In the (rather distant) future it may become possible to transplant marrow from somebody who is not a Perfect tissue match with the patient.


Well, what about other possibilities?
         "Genetic Engineering" might be used to transplant a healthy globin gene into patients with thalassemia. The molecular biologists are very hopeful that this might be possible in the more distant future (10-15 years).


How would that be done?
         It would be necessary to take some bone-marrow from the thalassemic person, grow it in tissue culture, and infect it with a sort of artificial virus carrying the healthy gene. The "virus" would cut out the unhealthy gene and replace it with the healthy one. The cells would then be tested, and put back into the thalassemic person.


How would you put them back, would it be like bone-marrow transplantation?
         Yes, the corrected cells would be put into a blood bad and run into a vein, so that they could "home" to the patients bone-marrow. But they would only be able to settle in the bone-marrow if the thalassemic marrow was first killed off, as it has to be before bone-marrow Transplantation.


Does this mean that there would be some risks then?
         Yes, there are bound to be some risks, but they should be less than for bone-marrow transplantation. At present it does not look as if gene therapy will be a simple solution but it may be a way of making a bone-marrow transplantation available to everybody. It is also likely to be a very expensive procedure, not easy to do in developing countries.


Aren't there any other "Genetic Engineering" ideas?
         Yes, there is one, called "Reversing the Fetal Switch" In Chapter 1 we explained that the fetus and new born baby have fetal hemoglobin (HB F), and normally they switch over to adult hemoglobin (HB A) in the first few months of life. Thalassemic patients only develop a problem when they try to switch over to Hb A, because their "Fetal Switch" does not work properly. Scientist hope that if they can learn enough about the switch, they might be able to switch it back again for thalassemics. It you only made Hb F, as you did before you were born, and if you made enough of it, and did not try to make Hb A, you would probably be quite well.
         However, so far it has been very difficult to find out much about the fetal switch.


Are you trying to say that there is no hope whatever of a simple cure, by taking tablet or something?
         It might be possible in next 50 years, but we do not except to have a really simple cure for patients living today.
         It is nice to dream of a solution, but the most realistic hope at present is for a cheap oral iron chealtor, that would let thalassemic patients in European countries feel nearly cured, because they would only have to have regular transfusions, and would put a nearly normal life within reach of patients in developing countries.
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