Medical Health Encyclopedia

Pemetrexed (Alimta). Pemetrexed (Alimta), known as an anti-folate, is another promising new agent for second-line therapy and possibly for first-line treatment as well. The drug targets a number of enzymes that play a role in cancer cell proliferation. Some research suggests that it is as effective as docetaxel. Pemetrexed does have some serious toxic effects, but they can be significantly reduced with folic acid and vitamin B12 supplements. It is then less toxic than docetaxel (when docetaxel is given every 21 days but not weekly).

Gefitinib (Iressa) and Other Tyrosine Kinase Inhibitors. Much research is focusing drugs that block small molecules involved with the growth of blood vessels that feed the tumor (a process called angiogenesis). The spread of new blood vessels is controlled by compounds called growth factors, which may be important in cancer cell proliferation. Researchers, then, are interested in agents that literally turn off these growth factors or their receptors, such as epidermal growth factor receptor (EGFR). In so doing, the agents may be able to cut off cancer's life blood.

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Gefitinib and erlotinib are angiogenesis inhibitors that target receptors of an epidermal growth factor called tyrosine kinase.

• Gefitinib (Iressa) was approved in 2003 as a second-line therapy for non-small cell lung cancer. Many patients report significantly improvement in symptoms and quality of life and the drug initially showed great promise. In one study, gefitinib reduced tumor size by 50% in about 10% of the patients. However, recent large-scale clinical trial results have failed to confirm any survival advantage for most patients. At this time, it is not clear whether the drug will remain on the American market. Its manufacturer has withdrawn the drug's application for the European market.
• Erlotinib (Tarceva) was approved as a a single agent second-line therapy in November 2004. Study results show that the drug prolonged survival by several more months than placebo (6.7 versus 4.7 months). Erlotinib is administered orally and has very low toxicity (rash and diarrhea are common).

Combinations of Chemotherapy with Surgery, Radiation, or Both