How Are Lead Molecules Useful in Drug Discovery?
Developing a new drug can take up to 15 years and over $1 billion by the time it is approved. The cost associated with drug development and the amount of time it takes to get approval is often spread out over a few different phases. After a potentially useful drug is discovered, it must undergo intensive preclinical research, followed by actual clinical research. Once it is confirmed to be safe and effective, a drug must also wait for FDA approval and this can sometimes last anywhere from six to ten months. The time and money spent in research and approval are an inevitable part of the process. However, one of the most time-consuming and costly stages of the development of any drug is the time spent in a lab, discovering and isolating potentially useful compounds. The Beginnings of Lead Discovery
In the 1970s, researchers began to see the value of identifying biological pathways that could potentially be used to alter how a particular disease process works within the human body. These pathways, now termed biological targets, are the means by which disease processes negatively affect the body. By exploring how these biological targets – often proteins – can be altered to therapeutically benefit a patient by slowing or halting the disease process, researchers began to identify which biological targets could also be druggable targets. A druggable target is a biological target that has the capability to bind to a drug and affect its function. There are vast populations of proteins and other receptors within the human body and identifying which targets can be altered by which types of drugs can be a painstaking, time-consuming process. Fortunately, the use of lead molecules can drastically improve drug discovery times. What Are Lead Molecules? Instead of testing an assortment of drugs on one particular biological target, lead discovery focuses on indexes of compounds that have a known potential to interact successfully with a particular biological target. Lead molecules often have properties that necessitate further development and modification to be therapeutically useful. Molecules with a less-than-optimal structure allow researchers to work on developing a chemical structure that will eventually have the desired results on the target. Lead generation can be achieved in a few different ways, including:
Random screening. This method screens all compounds from an indexed series for potential use.
Non-random screening. This method screens only compounds that have been identified as similarly structured to a particular molecule that may have drug potential.
Metabolism studies. In some cases, the way a current drug is metabolized can lead to insights about the effects on other enzymatic activities.
Clinical observation. Many drugs have multiple effects on the human body. Through clinical observation, researchers can identify how lead molecules affect other biological pathways.
Lead Molecules Have Time and Cost Saving BenefitsToday, researchers can simultaneously conduct testing on thousands of different samples at once with the use of high throughput screening. By preparing multiple assay plates of as many as 6,144 wells each and utilizing robotics, data control software, liquid handling devices, and ultrasensitive detection methods, researchers can test hundreds of thousands of samples and identify hundreds or thousands of potentially useful molecules at once.
Lead molecules that are identified from these vast samples can then undergo lead optimization procedures to make them more likely to positively interact with the desired biological target. High throughput screening can identify which of these compounds has a positive effect on one or many targets, hastening drug discovery and reducing the overall cost of the process. In this way, lead discovery can help researchers and consumers alike.
The Future of Lead Molecules and Drug DiscoveryThe continued use of lead molecules has the potential to reduce the cost of drug discovery in the future. As researchers are able to catalog and maintain indexes of potentially useful compounds, both the cost and time to clinical research trials stands to improve. Overall, the benefits of lead molecule usage could positively impact the price of the resulting drugs in the long run.