Clinical trials

The newspapers have been reporting about the use of a leukemia drug for treatment of Multiple sclerosis.

Multiple sclerosis is a progressive disorder where the immune system starts producing autoantibodies against the central neuron system leading to demylineation of the neurons and thereby destroying the neurons. Generally, the immune system fights against invasion by foreign molecules by producing proteins known as antibodies. During development the immune system is fine tuned so that it would not destroy any of the body's proteins. However, sometimes the immune system becomes a rogue and starts destroying the body's own proteins. Such a condition is known as autoimmune disorder. This is what happens in multiple sclerosis where the immune system particularly destroys the neurons. There is no cure for the condition. Indeed there is no cure for any autoimmune disorder.

Thus, the news that a leukemia drug has potential to stem the damage caused in multiple sclerosis is a big news item.

Unfortunately, the newspapers have a tendency to hype without taking the consequences into consideration. We live on hope. Especially those of us who have life-threatening diseases. Wouldn't a miracle drug cure of us of our ailment?

The problem is that the leukemia drug has been used in clinical trials to treat multiple sclerosis. It is not available in the market. Moreover, the jury is still out on whether it is indeed a miracle cure or not. There has been some success in phase II trials. The drug has to go into phase III and then further tests before it can, if at all, be marketed as a treatment for patients with multiple sclerosis. There is a further rider on it: Only those patients suffering from early stages of multiple sclerosis.

Drugs are a funny business. Once a chemical compound is identified as having an effect on a protein such that it stops its function, the hard work starts. The next step is to prove that it would have effect on cells grown in laboratory. Then we have to find out how much of that chemical would be needed to say kill 50% of the cells. If all this is successful, then we need to show that it would indeed work on a mouse model. Further, we have to show that it has minimal (no compound exists that is not toxic at some level)side-effects. Then these tests have to be repeated in other animal models. Finally, we approach the clinical trials. There are five phases of clinical trials to pass before FDA will even consider giving approval. A rough estimate is that it can take anywhere between 20-25 years from finding a chemical molecule to getting into the market. The success rate of a chemical molecule becoming a drug is an abysmal 1%. 99% of the promising compounds fail along the way.