When the answers to most of these questions have been answered satisfactorily, then the test is likely to be considered clinically useful for specific situations.

How does a patient and his or her doctor decide whether a test is right for them?
Patients and doctors should consider the condition that the patient has, their history of drug-related side effects and/or adverse drug reactions, the drug therapies that are available, and the uses the test is intended for. Pharmacogenomic tests are not meant to stand alone but are meant to be used in conjunction with the patient's other clinical findings. Does the doctor understand how to interpret and utilize the results? How is he expecting the results to affect the patient's current and future treatment? Doctors and patients should both understand why they are performing the test.

How are drug discovery, development, and marketing affected by pharmacogenomics?
In the past, drug companies have focused primarily on blockbuster drugs – drugs that could be marketed to a large portion of the general population. Each of these drugs took hundreds of millions of dollars and years of research and clinical testing before it was cleared by the FDA and released to the market. For every blockbuster, there were numerous drugs that were orphaned (shelved) during the development process. Some of these drugs were only effective for a small percentage of those enrolled in clinical trials; others had too many associated side effects and complications.

Each of the blockbusters released was also associated with rare but sometimes serious complications, and some complications that were not evident during clinical trials emerged with long term use. When a large number of people began taking these medications, even a tiny percentage of rare complications could become a significant number of affected patients. In some cases, these blockbusters have had to be removed from the market and/or their benefits versus their risks weighed carefully by the patients taking them and the doctors prescribing them.

With pharmacogenomics, new drug development could be sped up in a couple of ways. First, the human genome project and advances in the mapping and collecting of specific types of genetic variations (called Single Nucleotide Polymorphisms (SNPs), haplotypes, and microsatellites) have made it potentially easier for drug companies to identify genes of interest (those in which genetic variation is strongly associated with an identifiable disease) and targets of interest (the functioning of specific enzymes, proteins, or receptors that can be used as drug targets to block, inhibit, replace, or enhance the action of the target and have an effect on the condition).

And second, it can make it easier to identify the population most likely to benefit from the drug being developed. The results of phase I and phase II clinical trials (performed for safety and effectiveness) can be evaluated to determine common factors in patients who responded versus those who did not or who had significant side effects. Some of the orphan (shelved) drugs may be able to be reevaluated and retargeted at those most likely to respond. In the future, drugs and the tests used to determine who would be likely to benefit from them may be developed simultaneously.

Other Concerns

Some patients and their advocates have concerns that pharmacogenomic test results might be used to discriminate against patients who have a genetic risk for health problems. Insurance carriers may mandate testing prior to approving drug therapy or require testing of family members. Patient privacy is an issue as with other genetic tests. These and other issues are currently being debated and addressed by members of the medical community, insurers, government agencies, and a variety of national organizations.