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What is a Phase 3 Clinical Trial?

January 20, 2023
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What is a Phase 3 Clinical Trial?
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Treatments that have been proven to be effective in phase II clinical trials must surpass one more phase before they are approved for general use. Phase III trials compare the safety and effectiveness of the new treatment with the current standard treatment.
Since doctors have not yet determined which treatment is better, study participants are often picked randomly (called randomized) to get either the standard or the new treatment. When possible, neither the study doctor nor the patient knows which treatments the patient is getting. This type of study is called a double-blind study. Randomization and blinding are discussed in more detail later.

Understanding Clinical Trials Phases

Clinical trials follow a specific timeline, from early, small-scale, phase 1 clinical studies to late-stage, large-scale, phase 3 studies. There are many clinical trial phases involved in developing new treatments. Each phase of clinical research is an essential part of developing drugs and treatments.

Purpose of Phase 3 Clinical Trials: Efficacy and Monitoring of Adverse Reactions

The purpose of phase III trials is to evaluate how the new medication works compared to existing medications for the same condition. To proceed with the clinical trial, investigators must demonstrate that the medication is at least as safe and effective as standard treatment options.

Key Points of Phase 3 Clinical Trials

  • Most phase III clinical trials include a larger number of patients, at least several hundred.
  • These trials are often conducted in many places across the country (even around the world) at the same time.
  • Phase III trials are more likely to be available in local community hospitals and doctors' offices.
  • Phase III trials tend to last longer than the first two phases of clinical trials.
  • Placebo treatments may be used in some phase III trials, but they are never used alone if there's a treatment available that works. Sometimes, a participant who is randomly assigned to the placebo as a part of the study will, at some point, be offered the standard treatment as well.

Like other phases of clinical trials, participants in phase III clinical trials are monitored closely for side effects, and treatment is stopped if they become too hard to manage.

Number of Participants

Phase 3 studies are tested over a longer period than phase 1 or phase 2 studies and include many more participants with the targeted disease, often between 300 to 3,000. By testing more participants, researchers can more confidently see if the investigational treatment has any adverse effects.

Uses of Treatment Groups

A phase III clinical trial involves a much larger group of participants and emphasizes determining whether the treatment would be safe and effective for many people. The research design normally involves assigning volunteers to treatment or control groups. There can be more than one treatment group, especially if the treatment involves a combination of drugs or different elements. Again, there is a control group that receives either the current standard treatment or a placebo treatment.

Uses of Placebo

Placebo treatments may be used in some phase III trials, but they are never used alone if there's a treatment available that works. Sometimes, a participant who is randomly assigned to the placebo as a part of the study will, at some point, be offered the standard treatment as well.

Efficacy and Monitoring of Adverse Reactions

A Phase III clinical trial collects more information about safety and effectiveness, studying different populations and dosages, and using the drug in combination with other drugs.

While a study treatment is being examined, participants are closely monitored for side effects, longer-term effects, and possibly other things such as quality of life or survival. By testing multiple study treatments, researchers can see, for example, how new and existing treatments can be best used to treat the health condition in question.

Length of Study

Phase III studies usually take from 1-4 years. This phase is designed to determine the drug’s long-term effects.

The Food and Drug Administration FDA usually requires a phase III clinical trial before approving a new medication. Due to the larger number of volunteers and longer duration of phase III, rare and long-term side effects are more likely to appear during this phase.

If study investigators demonstrate that the medication is as safe and effective as others publicly available, the FDA will usually approve the medication.

If the results show that the experimental treatment didn't work better than the current standard of care or even caused an acceleration of the disease or other unexpected severe adverse events, the FDA may not permit the treatment to proceed to apply for a New Drug Application.

If it does show that the experimental treatment worked better than the current standard of care, the pharmaceutical company can proceed to a New Drug Application. This NDA contains all of the discoveries at every phase of the process (from the Basic Research/Drug Discovery until the results of the Phase III clinical trials) and is submitted to the FDA for consideration to approve the sale of the treatment.

Interested in Enrolling in a Clinical Trial? Call Santos Research Center today!

Enroll in our open research studies and join us in helping future patients at Santos Research Center, Corp. now!

At Santos Research Center, Corp., we have completed over 400 clinical trials. We make use of efficient and reliable systems to plan and manage quality medical research studies.

For more information about Phase III clinical trials, you may visit us at www.santosresearch.com.

If you are interested in participating in a clinical trial, call us at (813) 249-9100.

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