Drug To Cure Cancer : Thalidomide
The Thalidomide Dilemma
In the late 1950s, a new drug called thalidomide was widely sold as a sleeping pill and cure for morning sickness during pregnancy. Research had shown that thalidomide is remarkably non-toxic, even in very high doses. Tragically, tests did not show that the drug affects the normal development and growth of a fetus. As a result, thousands of women who had taken thalidomide when pregnant gave birth to babies with missing or malformed limbs, facial deformities, and defective internal organs. The drug was banned for general use in 1964. In the years since the catastrophe caused by thalidomide, researchers have discovered more effects that the drug has on the body. Not only does thalidomide induce sleep and reduce nausea, but also it is a powerful anti- inflammatory agent. It can also moderate extreme and damaging reactions of the immune system. These effects make it a valuable tool for treating leprosy, rheumatoid arthritis, lupus, certain conditions associated with AIDS, and other diseases. The dilemma is how to control and market the use of a drug that can cause great damage, yet has great benefits as well.
One Drug, Many Effects
It is quite common to ﬁnd that pharmaceuticals developed for one purpose have other applications. For example, Aspirin™ was originally prescribed as a painkiller, but much later was found to help prevent the formation of blood clots. Prozac™ was marketed as an appetite suppressant before it was recognized as an effective antidepressant. Minoxidil™, used to control hypertension, is now used to treat baldness. The interactions between a particular drug and the body’s cells and organ systems are often complex and poorly understood, even after a drug has been in use for many years.
Thalidomide and Disease
How does thalidomide produce its effects? Since the mid-1990s, scientists have learned that: Thalidomide inhibits the movement of cells needed to form new blood vessels. This is the property of the drug that affects fetal development and results in malformed limbs and organs. However, inhibition of blood vessel growth also has important clinical value. For example, cancerous tumours can only grow by developing new blood supplies to provide them with oxygen and nutrients and to carry away wastes. By preventing the growth of new blood vessels, thalidomide starves tumours and stunts their growth. Thalidomide suppresses the production of a chemical messenger called tumour necrosis factor, or TNF.
This chemical is made by blood cells as part of the body’s
immune response. However, large quantities of TNF result in harmful inflammation — a common symptom of autoimmune disorders such as rheumatoid arthritis, AIDS, and lupus. Thalidomide is the most effective drug known to relieve this symptom.