If you know anything about how cancer works, you understand that it is in essence uncontrolled cell growth. Unfortunately for pathology, these outlaw cells are basically the body’s own cells, not “foreign” or exogenous invaders such as bacteria or viruses. Therefore, the body’s own immune system will not attack cancer cells on its own initiative. Researchers are taking two approaches to this. One approach lies in deceiving the immune system into reacting to cancer cells as if they were exogenous pathogens. The other consists of stopping the growth of cancer cells. This is the strategy behind a recent drug called pemetrexed disodium. Marketed under the registered brand name Almita, it is a chemotherapy drug that has shown some promise in the treatment of mesothelioma and non-small lung cancer. From a chemical standpoint, pemetrexed disodium is not unlike Vitamin B9, better known as folic acid, which occurs naturally in leafy green vegetables such as spinach and peas. It is considered an antimetabolite, which unlike metabolites, inhibits cell reproduction instead of promoting it.
The details of exactly how pemetrexed disodium inhibits cell reproduction is rather technical, but if you remember high school biology and the mechanism of cell reproduction, you know that cells reproduce by division, a process known as mitosis. This is how all life reproduces, even human and animal life. The union of sperm and egg simply sets this process into motion. In order to accomplish this, the DNA and RNA, the genetic “blueprints”, must be replicated. Pemetrexed disodium creates conditions in cancer cells that prevent DNA and RNA from forming, thus halting the spread of the tumor. The U.S. Food and Drug Administration approved the drug for the treatment of mesothelioma and non-small cell lung cancer. Currently, it is undergoing trials for the treatment of cancer of the esophagus. Patients who undergo treatment with pemetrexed disodium must take folic acid and vitamin B12 supplements as well as steroid injections in order to prevent skin rashes that may result as a side effect. According to a U.K. study, there was “statistically significant” relief from pain, shortness of breath, fatigue, loss of appetite and cough among patients treated with pemetrexed disodium. Aside from skin rashes, patients may experience nausea, diarrhea, and a reduction in white blood cell count.