Drug Repurposing: Sustainably Accelerating Drug Discovery

By Dr. Luis Vaschetto, Ph.D.Reviewed by Megan Craig, M.Sc.

Repurposing existing drugs is a sustainable way to develop new treatments for diseases. Since repurposed agents have already been tested for safety and efficacy, bringing them to market is faster and cheaper than developing new drugs.

Repurposed medicines are also often more affordable than new ones, making them more accessible to patients around the world. Additionally, it is a strategy that can be used to identify new treatments for diseases that currently have no effective therapeutic options.

What is Drug Repurposing?

Briefly, drug repurposing can be defined as the process of finding new uses for existing drugs. It is a promising way to develop new treatments for diseases, and it can be especially useful for diseases that currently have no effective treatments or for which existing treatments are not sufficient.

Drug Repurposing as a Sustainable Strategy

Drug repurposing is a sustainable way to develop new drugs because it does not require the creation of new compounds, something that has become increasingly relevant to the pharmaceutical industry’s growing environmental impact.

Drug repurposing can also reduce the time and cost of bringing new drugs to market because existing drugs have already been tested for safety and efficacy in humans.

Drug repurposing can also be used to find new treatments for diseases that currently have no treatments. This is because existing drugs have already been tested against many different targets and diseases, so it is more likely that one of them will work against a particular disease.

Drug Repurposing Screening Approaches

The main drug repurposing screening approaches are as follows:

• Phenotypic screening: This approach involves testing approved drugs against a variety of cell lines or disease models to identify new therapeutic activities. For example, it is possible to test a library of already approved drugs against different cancer cell lines to determine if any of the drugs are effective in stopping the uncontrolled proliferation of cancer cells.
• Computational screening (pharmacokinetics modeling): Computational drug repurposing uses computers to predict new ways to use existing drugs. For example, a researcher might use a computer to predict how a drug interacts with different molecules in the body. This repurposing strategy is more sustainable than phenotypic screening because it is less resource-intensive and can be used to screen many drugs.

It is important to highlight that phenotypic and computational drug screening strategies complement each other, and laboratory assays are always required to test drug safety and effectiveness in vivo conditions.

Drug Repurposing: Accelerating the Development of New Treatments

Drug repurposing has been used to develop new treatments for a variety of diseases, including cardiovascular diseases, cancer, and erectile dysfunction. Some of the most widely-known repurposed drugs on the market include:

• Acetylsalicylic acid: Aspirin, a drug originally developed to relieve pain in the late 19th century, was found to have another use in the 1980s: preventing blood clots. It works by irreversibly inhibiting an enzyme called platelet cyclooxygenase 1 (COX-1), which is involved in producing thromboxane A2, a chemical that makes platelets stick together. By blocking the production of thromboxane A2, aspirin helps to prevent blood clots, which can reduce the risk of heart attack and stroke.
• Imatinib (Gleevec): Imatinib was originally developed to treat chronic myeloid leukemia (CML), but it has since been found to be effective against other types of cancer as well. This is because imatinib can block a variety of proteins that are important for cancer growth, such as Bcr-Abl, PDGF, VEGF, and bFGF. Imatinib can also reduce tumor pressure, making tumors more sensitive to other treatments. This strategy of combining different drugs is known as combined drug therapy.
• Sildenafil (Viagra): Sildenafil, a popular medication for erectile dysfunction, was originally developed to treat angina pectoris, a heart condition. It works by blocking an enzyme called PDE5, which breaks down a signaling molecule called cGMP. cGMP causes blood vessels to relax, so blocking PDE5 increases cGMP levels and leads to vasodilation. This increased blood flow to the penis helps men achieve and maintain an erection.

Sustainable Drug Repurposing: A Promising Future for Drug Discovery

Drug repurposing is a promising new approach that has the potential to change the landscape of drug discovery and improve the lives of patients around the world.

Repurposing strategies are rapidly evolving, accelerating the drug discovery process and making new treatments more affordable and accessible. Computational drug repurposing is more sustainable than other screening methods because it uses fewer resources and can test more drugs.

As computational tools continue to improve, we can expect to see even more new and effective treatments developed from existing drugs. In conclusion, drug repurposing strategies, especially computational drug repurposing, are revolutionizing drug discovery by bringing new treatments to patients faster and more efficiently than ever before.

Further Reading

• All Drug Discovery Content
• Exploring the Structure-Activity Relationship (SAR) of Drugs
• Hit to Lead (H2L) Process in Drug Discovery
• Hot Melt Extrusion in the Pharmaceutical and Food Industries
• How is Additive Manufacturing Used in the Pharmaceutical Industry?