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How Long Does a Phase 3 Clinical Trial Last?


A Phase 3 clinical trial is a pivotal stage in the drug or nutraceutical product development process. It is meant to determine the efficacy and safety of potential drugs or products before they reach the market. This phase typically lasts one to four years, where the drug/product’s performance is rigorously evaluated in a larger and diverse population. 

The duration of a Phase 3 clinical trial is influenced by several factors, such as 

  • The complexity of the disease or health area 
  • The nature of the drug/nutraceutical product 
  • Regulatory requirements
  • The number of participants involved 

For instance, trials for chronic illnesses may require longer observation periods to assess the drug’s long-term effect, while short-term ailments might have shorter durations. The landmark Study of Heart and Renal Protection (SHARP) trial is a real-world example. In this trial, the researchers evaluated the efficacy of cholesterol-lowering drugs in patients with chronic kidney disease, which spanned over five years.

Here’s what you need to know about the complexity and duration of Phase 3 trials.

Key Takeaways

  • Phase 3 clinical trials are crucial in confirming the efficacy and safety observed in Phase 2 trials involving a larger participant group.
  • These trials have a typical duration of one to four years.
  • Phase 3 trials may extend the duration of observation to evaluate long-term effects and durability of response.
  • These trials compare the new treatment to existing standard treatments or placebos to determine its relative efficacy and safety.

What is the Purpose of a Phase 3 Clinical Trial?

Phase 3 clinical trials are a critical phase in the drug/nutraceutical product development process. This phase builds up on the findings of the earlier phases, particularly Phase 2. The primary purpose of Phase 3 is to confirm and expand upon the efficacy and safety of the results observed in Phase 2. However, unlike Phase 2, which typically involves a small participant group, Phase 3 trials cater to a larger group of participants. This large group provides a broader representation of patients who may benefit from the treatment.

Another key aspect of Phase 3 trials is comparing the drug or nutraceutical product being researched with preexisting standard treatments. In case there is no pre-existing treatment drug/product, a placebo is used. This comparison allows researchers to assess the relative efficacy and safety of the new drug or product and determine whether it offers superior benefits or improvements vis-à-vis existing options. Fortunately, Atlantia Trials offers the best clinical trial analyses.

In addition, Phase 3 trials also extend the duration of the observation to evaluate a drug or nutraceutical product's long-term effects and durability of response. This longitudinal assessment helps researchers understand how the treatment performs over an extended period and whether its benefits persist. 

If you’re looking for clinical expertise, try services by Atlantia Trials.

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What Are the Next Steps After a Phase 3 Clinical Trial?

After completing a Phase 3 clinical trial, the next step may typically involve seeking regulatory approval from agencies like the FDA in the U.S. or the EMA in Europe. Successful approval allows the drug or nutraceutical product to be marketed and made available to the public for its intended use.

After receiving regulatory approval, drugs usually enter Phase 4 trials. Phase 4 trials aim to monitor the long-term effects, efficacy, and safety of the drug in a broader population beyond the controlled setting of the clinical trials. 

Phase 4 provides additional data on the drug’s performance in real-world practice. This helps researchers and other healthcare professionals make decisions and further research. As a researcher, you can learn a lot about defining objectives and endpoints in clinical trials here.

Overall, completing a Phase 3 trial marks a significant milestone in the drug or nutraceutical product development process. However, this is just one step in the journey towards making the treatment available to patients. Regulatory approval and ongoing monitoring through Phase 4 Trials are essential to ensuring the safety and effectiveness of new medications in clinical practice.


Knowing how long Phase 3 trials last is crucial to navigating the drug or nutraceutical product development landscape. To recap, the duration ranges from one to four years — a time frame pivotal to assessing the drug or products’ safety and long-term use. 

Several factors come into play when determining the duration of a Phase 3 clinical trial. These factors include disease complexity, participant recruitment, long-term observation, and regulatory standards. If you’re thinking about being part of a clinical trial, learn more here about why you should take part in a clinical trial.

Before you go, remember to stay informed about the meticulous process behind life-changing medications and research. Take the next step in medical research by exploring topics and opportunities with Atlantia Trials. Furthermore, read here if you’re looking for clinical trial types in nutraceutical research.

How Long Does a Phase 3 Clinical Trial Last: Frequently Asked Questions

Here are some commonly asked questions about how long a Phase 3 clinical trial lasts:

Is Phase 3 the Last?

Yes, phase 3 is the last phase before seeking regulatory approval for a drug’s public use. However, phase 4 comes after phase 3—a phase for gathering more data on a drug’s effectiveness and potential long-term side effects through post-marketing surveillance.

Why is 3-Phase Considered Better than 4-Phase?

Phase 3 being considered “better” than Phase 4 is a general misconception. Phase 3 trials are crucial for confirming efficacy and entail monitoring adverse reactions in a controlled setting. In contrast, Phase 4 studies focus on assessing long-term effects in real-world settings in a broader population. Therefore, both phases are essential for ensuring the safety and efficacy of a drug or nutraceutical product before and after regulatory approval.

What is the Difference Between Phase 2 and Phase 3 Trials?

Phase 2 trials assess the efficacy and safety of the drug or nutraceutical product in a small group, while Phase 3 trials confirm the efficacy and safety of the drug or product compared to other treatments in a larger group. Moreover, Phase 3 also focuses on regulatory approval with randomized controlled tests. If you want more information on the different types of clinical trials, read here.

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