Mesothelioma Clinical Trial Phases 0-4

Quick Summary

There are different stages, or types of clinical trials called phases. Potential new drugs move through these various stages to help researchers determine if they are safe for humans to take if the medicine treats what it is supposed to address and what the best dosage is to get the desired results.


It’s important for all new treatments to move through FDA-regulated mesothelioma clinical trial phases.

Mesothelioma clinical trial phases ensure that all new treatments meet the highest safety and effectiveness requirements. Many, but not all, treatments in clinical trials become legally approved treatments and are made widely available to be patients.

Here is what patients who are interested in participating in a clinical trial should know:

  • There are 5 different mesothelioma clinical trial phases, each have their own focus, risks and benefits
  • Phase 0 looks at how the drug acts inside a patient’s body
  • Phase 1 focuses on finding the best dosage
  • Phases 2, 3 and 4 look at how well the drug works and how safe it is over longer periods of time
  • Early studies are usually only conducted at major cancer centers, but later trials can be run in smaller community-based oncologist offices
  • For more information on participating in a clinical trial, request a FREE Mesothelioma Help Guide

What Are Mesothelioma Clinical Trial Phases?

Preclinical trials are tests conducted on cell cultures or animals. They show researchers whether a drug works or is safe on a fundamental level.

Preclinical tests cannot show researchers whether the drug is safe or will react as expected for humans, which is why drugs undergo clinical trials. Before researchers can start using the drug widely, they first must prove it’s safe and effective in humans without harming the participants. This is why clinical trials are divided into phases.

There are 5 different mesothelioma clinical trial phases.

Early mesothelioma clinical trial phases help researchers determine a safe dosage and whether the drug works as expected. Later stages assess how effective the new drug is compared to current treatments and how safe the treatment is long-term.

Clinical Trial Update

Once researchers can prove that their drug works and that the side effects are within an acceptable range of severity, the drug can be approved for wider use by the Food and Drug Administration (FDA).

Phase 0

The first clinical trial that some drugs might go through is Phase 0 trials.

These trials are exploratory studies. While Phase 0 trials are not mandatory, they can be helpful because they can quickly show researchers whether the treatment acts as expected based on results from preclinical trials.

Phase 0 studies, which usually have fewer than 15 participants, determine how the drug reacts inside a human body:

  • Does it reach the tumor?
  • How do the cancer cells respond to the medication?
  • Is there a problem with the way the body absorbs the drug?

Patients who participate in Phase 0 trials receive very low doses for a short time. They then undergo additional scans, blood tests and biopsies so researchers can find their answers. There is minimal risk to the patient in Phase 0 trials.

The main benefit of participating in a Phase 0 trial is to help other patients down the road. Since the doses are so low, participants probably won’t see any benefit to themselves.

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Phase 1

All drugs must go through Phase 1 trials. This round of testing focuses on determining whether a drug is safe and what the best dosage is.

In Phase 1 trials, safety is the most important thing. While researchers will try to find a dosage that works, they are actually checking the side effects to make sure they are not too severe. How effective the drug is will be looked at later.

In this phase, between 20 and 100 volunteers are divided into small groups. The first group is given a low dosage of the drug. Researchers will then watch them to learn what the side effects are.

Clinical Trial Update

Only 70% of the drugs studied in Phase 1 trials will move on to Phase 2.

If the side effects aren’t too severe, the next group will receive a higher dosage. This process is repeated until the doctors find a dosage that works without causing dangerous or unmanageable side effects.

Phase 1 trials tend to be the riskiest for patients. There is also a good chance patients won’t see any benefit to their health because Phase 1 trials aren’t looking to see if the drug is an effective form of cancer treatment. They are only determining whether or not the treatment is safe to use in humans.

Phase 2

Once researchers find a safe dosage for the drug, the focus of the trials shifts to the effectiveness of the drug. There are many different ways a drug can be useful:

  • It can cause cancer to shrink or disappear
  • The cancer might not grow for an extended period
  • The patient might experience a longer than normal remission
  • The patient lives longer than they would have been expected to if they did not have the treatment

In Phase 2 trials, all the volunteers usually get the same dosage of the drug based on the results of the Phase 1 trial.

In some Phase 2 trials, patients are randomly divided up into groups. Different treatment groups receive the drug in different doses or in different formats to see which way is the safest and most effective manner.

Clinical Trial Update

Tests can last up to 2 years, and about 33% of drugs in Phase 2 trials move onto the next round.

The main focus of a Phase 2 trial is efficacy but researchers still closely monitor patients’ side effects. Now that several hundred individuals are receiving the drug, less common side effects might appear. Phase 2 trials are still usually conducted at major cancer centers, but they can be done in local hospitals or doctor’s offices.

Phase 3

In Phase 3 trials, the researchers compare the new drug with the current standard-of-care drug to see which works better, and which one has the more manageable side effects.

In Phase 3 trials, patients are randomly divided into different groups to ensure that the results are based on the treatment and not off of similarities between the patients. These trials are conducted as double-blind trials, which means neither the patient nor their doctor knows which drug the patient is receiving.

One group, called the control group, will receive the standard-of-care treatment. The other group will receive the new medicine. Sometimes placebos, or inactive drugs, are used in Phase 3 trials, but these will never be used on their own if there is already an effective treatment.

Clinical Trial Update

Between 300 and 3,000 patients participate in Phase 3 trials, which usually last between 1 to 4 years. At the end of the trial, between 25 and 30% of the drugs can move to FDA approval and Phase 4 trials.

If one group has better results or the new drugs side effects are too severe, the trial will be stopped early. However, if the new drug works the way it’s supposed to, the researchers can submit it to the FDA for approval so the general public can use it.

Because of the number of people needed in Phase 3 trials, they can happen in many locations across the country and sometimes even around the world, in community-based oncologists’ offices.

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Phase 4

Phase 4 is the final stage of clinical trials. In Phase 4 trials, researchers study the efficacy and safety of newly approved drugs in thousands of people over time.

While the drug is already approved Phase 4 trials still have many benefits:

  • Help researchers learn which side effects are short lasting and which ones last for a long time
  • Find rare side effects due to the number of people participating
  • Measure how effective the treatment is when it’s used with other procedures
  • Learn how the drug impacts a patient’s quality of life
  • Learn how cost effective it is to administer the treatment

Because the FDA has already approved these drugs, patients don’t need to enroll in a study to access it. By participating, patients help researchers understand why drugs work, helping them continue finding new and better treatments. Usually, it’s the safest trial because of the extensive research from previous mesothelioma clinical trial phases.

Participate in a Mesothelioma Clinical Trial

While there are risks involved in participating in clinical trials, patients suffering from mesothelioma deserve every treatment option possible. It’s may be worth your time to look into current clinical trials. Not only will you have access to new treatments before they are available, but doing so will also help you take ownership of your treatment plan.

For more information on mesothelioma clinical trial phases, contact our Patient Advocates today. Call us at (800) 584-4151 or sign up to receive a FREE Mesothelioma Help Guide to better understand treatment options like clinical trials for extending your mesothelioma life expectancy.

View Author and Sources

  1. American Cancer Society. “What Are the Phases of Clinical Trials?” Retrieved from: Accessed May 29, 2018.
  2. Center Watch. “Volunteering for a Clinical Trial.” Retrieved from: Accessed May 29, 2018.
  3. FDA. “Step 3: Clinical Research.” Retrieved from: Accessed May 29, 2018.
  4. National Comprehensive Cancer Network. “Phases of Clinical Trials.” Retrieved from: Accessed May 29, 2018.

Last modified: July 2, 2018