(RxWiki News) Some types of cancer treatment are on a molecular level, relying on interactions between growth receptor proteins on the cancer cells and drugs that target these specific receptor proteins.
Sometimes gene mutations in cancers can cause this interaction to fail, and the treatment is no longer effective.
Researchers at Johns Hopkins have found that a single mutation in the EGFR protein can cause high levels of resistance to several pharmaceutical treatments, including Erbitux (cetuximab) and Tykerb (lapatinib).
Researchers concluded that certain types of other drugs such as Tarceva (erlotinib) may be more effective in these cases of drug resistance.
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Future testing for the presence of these mutations in lung cancer patients may help oncologists avoid losing valuable time when treating patients with resistant cancers, focusing on treatments that will work. The research also explored why Erbitux and Tykerb have had promising results in laboratory experiments but have not always been effective in patient treatment.
These drugs focus on the growth protein EGFR, which is key in cancer growth. Many pharmaceutical treatments for cancer focus on the growth receptor family of proteins, but due to the unique nature of each cancer it is hard to know the best molecular target before beginning treatment. Research in this area strives to better organize cancer treatments for optimum patient outcome.
"We found that different forms of EGFR protein reacted in unexpected ways; and by sorting out these forms in advance, we may be better able to determine which drugs will be better candidates for future clinical trials,” said Philip A. Cole, M.D., Ph.D. professor at Johns Hopkins University School of Medicine.
“Many clinical trials that used cetuximab and lapatinib were unsuccessful,” says Dr. Cole elaborated, “and our findings suggest why they failed and why erlotinib succeeded.”
First approved by the FDA in 2004, Tarceva averages a three month improvement in life expectancy at a projected cost of $9,000 a month.
Results were published in Nature Structural & Molecular Biology.
Funding for this study was provided by grants from the National Institutes of Health. No other financial relationships were disclosed by the research team.
