A drug needs to pass quite a few hurdles before it gets to the market. The Conversation/Wes Mountain, CC BY-ND
Not every drug designed by pharmaceutical companies makes it to the market; very few do. Only 9.6% of new drugs in development in the years 2006-2015 successfully made it to the market to be used by patients. That’s because there’s quite a process a drug needs to go through to make sure it’s not only effective for what it’s designed for, but that it’s not harmful.
After animal trials, that provide essential information on the effects of the drug on vital organs and how toxic the drug is at different doses, the drug progresses to testing in humans. This is done through a number of clinical trials conducted over four phases.
The goal of these clinical trials is to show the drug is safe and capable of achieving a desired outcome when used as prescribed, with each phase gathering more information about the new treatment.
Once enough information has been obtained on a drug, regulatory bodies, such as Australia’s Therapeutic Goods Administration (TGA) and the US Food and Drug Administration (FDA), review the information on the drug’s benefits and known side effects. Only if the drug’s benefits exceed its harms is it allowed to enter the health market.
This is the first time a new drug is studied in humans. Phase one trials involve a small number of healthy volunteers (up to around 80) and provide information on the toxicity of the drug for a range of doses chosen based on the animal studies. If found to be safe, meaning safety concerns associated with dosing are considered acceptable, the drug enters the next phase.
This focuses mainly on the benefits of the drug: whether it improves outcomes or minimises the effects of the condition (disease) of interest, along with short-term safety. These studies typically include up to several hundred patients with the condition targeted by the new drug. If the drug is found to be acceptable in terms of the side effects and there is some indication it has some benefit to patients, then it progresses to the third phase.
Phase two trials typically explore a range of doses of the new drug to find the best dose for phase three.
Here, researchers seek to provide definitive answers on whether the drug is effective and safe. The number of participants involved and the duration of phase three studies varies across products and target conditions. Typically they involve hundreds and up to thousands of people.
If the combined evidence from the animal and human studies up to phase three indicates the new treatment is sufficiently safe and effective, approval is sought from a regulatory authority who may approve its commercial use.
It takes up to 12 years on average from a drug’s discovery in the laboratory to its approval by a regulatory body. from shutterstock.com
This is for when drug has been approved. Phase four studies often focus on the drug’s long-term effects while it is on the market. They may also involve investigations into the use of an already approved drug to treat a different condition or in a new population such as children.