Medical breakthroughs are usually a big deal – you’ve probably seen headlines about new treatments for difficult diseases. One of the leading goals of modern science is to develop new drugs that can manage previously untreatable diseases along with medicines that work better than previous versions. The journey from an idea in a researcher’s head to a pill in your local pharmacy often takes years of testing and perfecting.

Finding New Medicines

Historically, drug discovery began with the identification of a new substance produced by a plant or animal. We still use many of these drugs, such as penicillin from fungus and heparin from leeches. Modern science has offered a new way to discover medicines – today researchers can engineer molecules that they predict will target a disease precisely and develop compounds that mimic natural substances but carry fewer side effects and safety hazards. With the use of tools like AI, computer scientists are now even able to create models of potential new drugs without ever setting foot in a lab.

Discovery Takes Time

While TV often depicts discovery as a single “ah-ha!” moment, the reality is that the vast majority of promising potential drug ingredients never leave the lab. It is often the case that when a substance is good at impacting a disease, it also causes undesired effects in other parts of the body. Testing new compounds is critical to ensure that the next miracle drug does what it’s supposed to do without causing more harm than good. Scientists evaluate thousands of new ingredients every year, but only a handful of these will prove safe and effective enough to end up in the hands of patients.

Starting in Cells

When a new substance shows strong medical promise, one of the first stages of testing involves demonstrating that it is safe in lab-grown cells. Researchers grow human and animal cells in dishes and expose them to a range of dosages. This allows them to observe how the cells react and determine what doses might be effective treatments versus what might be toxic to a patient. Over the past decade, cell-based assays have become highly specialized and complex, such that researchers can now look at a drug’s effect on different organs, like the heart or liver, and accurately predict what will happen in the human body.

Animal Allies

If testing in cells suggests that a drug will be safe, the next stage is testing in animals. While modern cell-based assays provide a great deal of information and rule out many unsuitable drug candidates, it is not yet possible to predict exactly how a drug will behave in the complicated environment of the body from lab tests alone. Interactions between different cell types, the immune system, metabolism, and other complex bodily processes can lead to drug complications that could not be predicted by viewing cells in a dish. Animal trials help researchers determine if a new drug is suitable for humans to try and what dosages are likely to be safe in human patients.

Entering the Clinic

The final stage of drug testing is clinical trials. Once a drug has been deemed safe in animals, clinical trials work to confirm safety and demonstrate that the drug works the way it is intended to work. The gold standard for clinical trials is a double-blind trial, where neither the patient nor the attending doctors know which patients are receiving the drug and which are receiving an inactive placebo. Typically, a drug is run through multiple clinical trials in different populations, and if it consistently proves to be safe and performs better than no treatment, it will be approved for doctors to prescribe.

A Long Journey

The discovery of a new drug can take years to complete and is often the result of efforts by numerous researchers and clinicians. Each stage of development serves to increase medical knowledge and ensure only the best treatments make it to patients.