Epidemiologic and Clinical Studies
Studies of human populations have provided important information about the causes of many diseases, such as the relationships between cholesterol and heart disease, the mechanism of transmission of HIV, and chemical exposures and birth defects.
Scientists can “see” abnormalities—and track treatment progress—in the brains of victims of Alzheimer’s and Parkinson’s diseases, schizophrenia, epilepsy, and brain injury1 using sophisticated scanning technologies (CT, PET, and MRI). All drugs must undergo clinical testing before becoming approved; carefully crafted clinical research is the best way to determine human reactions to new drugs.
In Vitro Research
An enormous amount of valuable in vitro (test tube) research is conducted today. The National Disease Research Interchange provides more than 130 kinds of human tissue to scientists investigating more than 50 diseases, including cancer, diabetes, and glaucoma. Cell and tissue cultures are used to screen new therapies and to test for product safety. Genetic microarrays are being used to predict liver toxicity by measuring gene expression in human liver cells.2
In Silico (Computer) Technologies
Computers can often predict the toxicity of chemicals, including their potential to cause cancer or birth defects, based on their molecular structure. Computer simulations can also predict the metabolism and distribution of chemicals in human tissues.
Safety tests using human cells are more accurate than animal tests. In the Multicenter Evaluation of In Vitro Cytotoxicity tests (MEIC), researchers evaluated 68 different methods to predict the toxicity of 50 different chemicals.3 Rat LD50 tests4—lethal dose tests currently used—were only 59 percent accurate, but a combined human cell test was 83 percent accurate in predicting actual human toxicity.5,6
Pharmagene Laboratories conducts new drug development exclusively using human tissues and computer technologies. With tools from molecular biology and biochemistry, Pharmagene investigates how new drugs affect the actions of human genes or the proteins they make. These techniques replace animal tests in many cases.
1. Langley G et al. ATLA. 2000;28:315-331.
2. Kier et al. Mutat Res. 2004;549(1-2):101-113.
3. PCRM fact sheet, In Vitro Acute Toxicity Tests More Predictive Than Animal Tests.
4. PCRM fact sheet, Inadequacy of the LD50 Test.
5. PCRM fact sheet Rats: Test Results That Don’t Apply to Humans.
6. Clemedson C et al. ATLA 1996; 24:273-311.