As new diseases continue to emerge, researchers are working harder than ever to identify drugs that may be effective in halting their progression. Before a drug ever reaches the market, a complex process of compound identification and human safety evaluation must take place. This process, known as drug discovery, can take years to complete and can be very costly.
However, the drug development process is essential. It ensures that the drugs on the market are safe and effective. Securing a drug that is safe for humans is a crucial factor in maintaining a thriving, healthy population. During the drug discovery process, compounds typically undergo one of two methods of discovery – target-based drug discovery or phenotypic screening.
Target-Based Drug Discovery
Most drugs interact with a disease by addressing a particular target within the human body. In order to find drugs that will combat known diseases, researchers must find and identify the targets associated with a disease’s progression. In most cases, these targets are particular proteins that act as receptors or signals inhibiting some response in the body or propelling the disease forward.
After researchers identify a particular protein target, they must study the way other molecules interact with it. This is accomplished by screening a large variety of molecules and isolating those that interact with the target. If any protein/protein interactions serve to advance or inhibit the disease’s progression, researchers can formulate drugs to exact a similar, desired effect on the target.
Phenotypic Screening
Another method of drug discovery involves identifying molecules that have known properties or known effects on cells. In this method, known as phenotypic screening, researchers use cells or animal disease models to screen molecules and identify those that cause a change in the cell’s response to disease. Then, effective molecules can undergo further study to identify the mechanisms that led to the change.
Unlike target-based drug discovery, the particular disease-advancing target is not identified before screening begins. Instead, researchers look at the target and how it reacts to the screening molecule. This process, known as target deconvolution, reveals the target’s properties as well as the specific mechanism the screened molecule used to exert change on the advancement of disease.
Toxicity
In a recent study, only 50% of drugs that reached Stage III development actually made it to market, and toxicity is one of the most common reasons for drug failure. Identifying toxicity at an early stage can prevent labs from spending money on developing drugs that will never make it to market. High-throughput methods can be used within drug development to understand cell-level molecular interactions and identify toxic molecules early in the process.
As drug screening processes continue to evolve, the importance of understanding protein/protein interactions, cell signaling networks, and toxicity is increasing. Advances in cell modeling, the development of sample assays, and the ever-increasing library of knowledge regarding how potential targets and therapeutic molecules work will lead to shorter lead times and fewer failed drugs. In the future, lower development costs and shorter development times will result in medications that are able to fight some of our deadliest diseases.