Phases of Clinical trials

Safiya Reza - 4 October 2021

Once a clinical trial is approved to begin, it must proceed through a series of steps. These steps are referred to as “phases.”

Clinical trials, also known as clinical studies, are the means through which we can discover new ways to prevent, treat, and diagnose diseases. All the treatments that we now consider conventional were evaluated in clinical trials at one point or another. New treatments usually undergo a series of clinical trials to ensure that they are both safe and effective. Once a clinical trial is approved to begin, it must proceed through a series of steps. These steps are referred to as “phases.”

Though clinical trial phases and designs may differ for certain diseases and specialist medicines, such as cancer drugs or gene therapies, the following is a broad summary of each phase of a clinical trial for most medications:

Phase 1:

Researchers typically examine a new medication candidate in healthy participants during Phase 1 investigations. In most cases, Phase 1 involves 20 to 80 healthy volunteers.

A Phase 1 study’s main goal is to assess a novel drug candidate’s safety before moving on to more advanced clinical trials. A Phase 1 trial can answer concerns like how much drug is measured in the blood after delivery, how the medicine acts in the body and the side effects associated with increased dosage. According to the FDA, about 70% of drugs pass to Phase 2.

Phase 2:

In Phase 2 studies, researchers deliver the drug to a larger number of patients (typically up to a few hundred) with the disease or condition for which the drug is being developed to assess its effectiveness and safety. Phase 2 studies are primarily concerned with establishing the optimal dose or doses of a drug candidate, in order to determine the best way to administer treatment to maximise potential benefits while minimising risks. The FDA reports that 33% of drugs pass on to Phase 3.

Phase 3:

Phase 3 studies are designed to show whether a drug candidate offers a treatment benefit to a specific population, provide more extensive safety data, and serve as the foundation for product labelling. Typically, 300 to 3,000 patients from the patient populations for whom the drug is eventually designed are enrolled in phase 3 studies. Participants are randomly randomised to either the experimental drug or a control group that receives either the current standard of care or a placebo (a substance that has no therapeutic effect).

When one or more Phase 3 trials are completed, the researchers examine whether the drug has shown efficacy and an acceptable safety profile in treating a disease. If this is the case, the company can file a New Drug Application (NDA), which includes all the data and information obtained throughout the process, including the findings of Phase 3 clinical trial(s), as well as any other material required by the regulatory body. The NDA is submitted to the FDA for marketing approval (or similar applications may be filed to other regulatory bodies outside the US). An average of 25% of drug products succeeds and are approved for broader market testing by the FDA.

Phase 4:

These tests are carried out after a drug has been shown to work and has been granted a licence.

The goal of phase 4 trials is to find out:

  • more information about the drug’s negative effects and safety
    what the risks and advantages are in the long run
    how well the medicine works in a larger population

How does Kinomica help with clinical trials?

how does kinomica help with clinical trials


  • U.S Food & Drug Administration, FDA, 2019, Development & Approval Process | Drugs,

Further Reading:

Contact Us!

If you have any questions or need any further information, then please contact the Kinomica team – we are more than happy to help

“Our technology can look at over 10,000 proteins in one simple experiment and tell researchers exactly which proteins are activated and deactivated. This is hugely important and relevant for personalised medicine“

Jane Theaker, Kinomica CEO