An exciting new class of drugs has been recently approved by the FDA for the treatment of certain types of cancers. These drugs work differently than other drugs because they turn on and off sections of DNA in order to inhibit tumor growth. The drugs bring us closer to directly affecting the information that controls the human body; the information resident in the DNA.
One such drug, Zolinza (Vorinostat) produced by MERK pharmaceuticals was approved for the treatment of a form of cancer known as cutaneous T-cell lymphoma (CTCL). CTCL is a form of non-Hodgkin’s lymphoma which is a cancer of a type of white blood cell called the T-lymphocyte. Some of these cells reside in the skin and CTCL causes these cells to wildly mutate and grow. The disease progresses from producing red patches on the skin to tumors. In some cases the disease develops into what is called Sezary syndrome whereby the entire skin becomes red, swollen, thickened and painful.
Treatments for CTCL included therapies to try to slow down the growth of abnormal cells. These included ultraviolet light therapy, radiation therapy, and photochemotherapy in which the patient is given a drug to make the skin sensitive to ultraviolet light. After the drug is given the patient is exposed to ultraviolet light which helps to slow down cell growth. Treatments also included traditional cancer chemotherapies.
What is common to all of the above treatments is that treatment is given after the tumors have formed. This treatment paradigm follows traditional cancer treatments. Some process in the body has gone awry producing tumors and the treatment is aimed at either destroying the tumors or the cells that produced them in the first place.
Most medications work this way. The body develops an abnormal process and the drug targets the result of the process. A better approach would be to correct the process before it develops.
This is the hope of new drugs that work on an epigenetic level. Epigenetics is the science of turning on and off portions of DNA without affecting the DNA itself. Epigenetic agents work by affecting the information flow from the DNA to the cell. They work closer to the origin of the dysfunction rather than on the result of it.
Zolinza works by inhibiting an enzyme called HDAC (histone deacetylase) that works closely with DNA. Excess amounts of HDAC are produced in cancer causing prevention of the activation of genes that control normal cell activity. In other words if there is a lot of HDAC in the cell then the genes that suppress tumor growth cannot work. If HDAC is inhibited then tumor growth is also inhibited.
So far there is good evidence that this approach is effective in treating CTCL. It is not perfect and like other drugs there are side effects. The body is a complex information system with DNA as the source of much of this information. Perhaps someday we will understand our existence in terms of complex structures of information and will work to correct the flow of information much like communication systems control errors. Drugs like Zolinza bring us one step closer to true informational medicine.