Pharmacogenomics as defined most simply is the ability to understand how different genetic variances play a role in how different people's bodies handle and break medicines and medication.
Researchers have always known through pharmacogenetic testing that genetic differences play a huge role in how people metabolize drugs, and the impact that can have on a certain drugs' efficacy. Different genes play very important roles in how the body distributes the drug, breaks it down, process it, and quite the overall effect that drug may have on an individual.
Recent developments in Pharmacogenetics, which is the study of how drugs interact specifically with certain genes and genetic expressions, is making precision medicine possible.
Up until now, if you had a heart condition or were suffering from cancer, there was a wide range of drugs that could have been used and doctors and pharmacists were left to discover through trial and error what worked and what would not. Certain drugs were known to work better for certain conditions and that was the amount of it. Certain people did not respond well to certain drug therapies and this was harmful for a number of reasons. Either people suffer from complications from medicines that were intended to be helpful but may have been inefficient at treating the illness or caused complications that were detrimental to the patient. Valuable time was lost trying to discover which medical compounds worked and those did not.
Pharmacogenomics changes this equation in a big way. Many people have been to a doctor numerous times with the same condition or problem, and have to go through different medicines and approaches before an issue is resolved. Pharmacogenomics removes much of this trail and error or “let's try a different medicine” approach. With the ability to understand exactly how certain drugs interact with certain genetic expressions medicines are able to custom tailor to specific illnesses and individuals. For someone suffering from a serious condition or illness such as cancer the benefits that pharmacogenomics offers are immense. Firstly cancer drugs and treatment are incredibly expensive, and more importantly time is limited with certain aggressive cancers and illnesses. With genetic medicine, it's possible to screen an individuals gene prior to determining a treatment path, and more accurately understand the best medicine for that certain individuals treatment.
The idea that we can understand down to the molecule what medicines will work and which people have a better success rate using which drugs is astounding and the benefits are immense. At this point the technology exists and is being utilized in a broad number of medicinal aspects but there remain many, many genes that need to be sequenced in order for pharmacogenomics to really take off.