How Do New Drugs Gain FDA Approval?

As of this writing, there are 36 COPD medicines currently in the pipeline. These are medicines that might help us breathe easier in the future. So, how does a drug get from idea to FDA approval? Here’s what to know.


Here you have researchers working in a lab. They may begin with a COPD gene. They see that this gene makes a certain protein. Perhaps this protein is Interleukine 8 (IL8). They learn that some people with COPD have elevated IL8 levels. So, this piques their curiosity. They decide to investigate IL8 further.

This is something that really happened. Researchers investigated IL8 and they learned that it is responsible for recruiting neutrophils to airways damaged by inhaled irritants (like cigarette smoke). They studied this further and discovered that neutrophils cause very aggressive airway inflammation. It is this, they think, that leads to the gradual development of COPD.

This further heightened their curiosity. They asked questions like, “What if we can develop a chemical to block the effects of IL8?” It was questions like this that lead to the discovery of a chemical produced by GlaxoSmithKline (GSK). The chemical is called GSK1325756 (now known as Danirixen). Here we have a discovery.1

Preclinical research

Our new chemical is now tested in a lab. The test subjects are animals. This type of research is necessary before testing can be done on humans. Many questions must be answered here, including:

  • Does the drug offer the intended result?
  • What is the best mode of delivery (pill, syrup, injection, etc.)
  • What is the best dose? How often should the drug be given?
  • Is it safe (very important here)?

These are all things determined before it is tested on humans. Now, animals are not humans obviously. So, will the drug have the same effect on humans? If a drug still looks viable after being tested on animals in a lab, it will then be tested on humans. After completing preclinical testing, chemical GSK1325756 looked very promising and was pushed forward.2-4

Clinical research

This is where our new drug is tested on humans. There are five phases of clinical trials on humans.5-7

  • Phase 0. Here, our chemical is tested on 10-20 volunteers. The goal is to see if it is safe to use on humans. The volunteers are closely monitored for side effects. This phase usually lasts only a few months. Our drug passed this phase.
  • Phase 1. Again, the potential drug is tested on a small number of subjects. The goal here is to determine what is the best dose to use on humans. Some subjects are given a low dose. Others are given a higher dose. At what point do side effects appear? This phase lasts only a few months.
  • Phase 2. Here the chemical is tested on larger groups of volunteers who are in the intended treatment population. In our case, Danirexin is tested on people with COPD. Various questions are answered here, such as 'Does it improve lung function?' These studies can be intense. They may last for several years. Danirexin passed this phase.
  • Phase 3. This is the phase where we currently find Danirixen. It is now being compared to other drugs currently used for COPD. The goal is to learn if our drug is as safe as other COPD medicines. Does it work the same or better than other COPD medicines? These studies will involve many people living with COPD. The volunteers are divided into two or more groups. An experimental group will receive Danirixen. The other groups may receive another COPD medicine or a placebo (fake medicine). The different groups are needed for comparison. This phase can also last for many years. Once a potential medicine passes this phase it moves on to FDA review.
  • Phase 4. This is testing done after FDA approval. This is when FDA approved drugs are further tested. These studies are nice because they may involve hundreds of thousands of subjects. These studies will show if there are side effects that show up after taking the medicine over a period of years. They will show if the medicine continues to work as intended after using it over a period of years.


Danirexin is not quite here yet. This is where the FDA reviews the results of all these studies. If everything looks good, our medicine will gain FDA approval. It can then enter the market and be placed on shelves in pharmacies. You and your doctor can then discuss whether you might benefit from trying the new medicine. Phase 4 clinical trials will start.

So, there are many steps between idea, drug development, and FDA approval. Many studies must be done to prove a medicine is both safe and effective for COPD. Danirexin looks like a promising treatment for COPD. We will continue to monitor as it moves toward FDA review.

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This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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