Early Phase Clinical Trials: Phases & Reasons to Enroll

early phase clinical trials
early phase clinical trials

What Are the 4 Phases?

Clinical trials are an essential cog in developing modern treatments for various diseases. Each trial is designed to uncover whether a treatment works, how well it works, and if it offers better outcomes than existing treatments.

A clinical program flow chart follows multiple clinical trial phases, each designed to answer different questions. With more than 130,000 active clinical trials in the U.S., thousands of participants are contributing to the future of medicine.

Here’s what you need to know about clinical trials; from early phase clinical trials, the clinical trial phases flow chart, and why you should consider enrolling in a trial.

What are the Purposes of Clinical Trials?

Clinical trials are designed to determine if a new drug is safe and effective. They assist researchers to discover new cures for serious diseases, such as cancer.

The purpose of each phase of a clinical trial is to answer a different question. The most important questions are whether a new treatment is safe, if it works and how well it works, and whether it surpasses existing therapies.

Determining safety is key in clinical trials. While no treatment will have zero potential for side effects, medical practitioners must balance any side effects with the benefits of that treatment.

Results from each phase of a clinical trial will eventually be submitted to regulatory bodies for drug approval if a treatment is has enough data to show it is safe and effective.

Are Clinical Trials Safe?

When it comes to clinical trials, safety is a massive consideration for the healthcare industry and those who choose to participate. Without willing participants, clinical trials cannot go ahead. The priority within any trial is the safety of those who enroll.

Within the U.S., clinical studies are regulated by the U.S. Food and Drug Administration (FDA). An independent panel of doctors, researchers, and other experts, known as an Institutional Review Board (IRB), is responsible for reviewing, monitoring, and approving each study.

The IRB measures clinical trial safety, protects patient welfare, and guarantees the rights of participants. This panel will also ensure that the potential benefits are balanced with risks deemed reasonable.

Remember that preclinical tests will be performed long before a clinical trial is ordered. These tests typically involve years of theoretical and practical research. Both in vitro and animal studies will come before human testing begins.

The fact that so much time and effort are put into preclinical tests ensures that safety standards are maintained in clinical trials.

Of course, no clinical trial with a new drug will ever be 100% safe, but the scientific community makes every effort to protect the health and well-being of all its participants.

Phases of Clinical Trials

Before treatments enter the mainstream healthcare system, scientists, doctors, and researchers follow the clinical trial phases flow chart. The flow chart includes four steps, each with a separate clinical trial design.

If the results from each phase lack promise or pose safety concerns, the entire trial can be stopped at any point. For example, if a drug causes serious harm to a participant in one phase, further phases may be suspended until more research can be carried out.

Types of Clinical Trials

There are two major types of clinical trials: drug trials and device trials. Each one has a different purpose.

  • Drug Trials – Drug trials test the efficacy and safety of drugs. Drug trials also uncover how quickly a drug moves through the body (pharmacokinetics) and how the body reacts to the drug (pharmacodynamics).
  • Device Trials – Medical devices are products within healthcare that do not require metabolism or chemical action. Medical devices could be anything from robotic surgical assistants to tongue depressors.

Phase I Trials

Phase I clinical trial design is the first mandatory phase of any trial. The goal of researchers is to determine whether a proposed treatment is effective and safe. Researchers will get an idea of side effects and the correct dosage.

Trials that move into this phase will use a small number of subjects. Typically, a minimum of 20 people and a maximum of 100 people is ideal for a treatment going through this stage.

According to the FDA, approximately 70% of drugs in phase one will qualify for the next phase.

Note that phase 0 trials do exist. These are not mandatory and may or may not involve human testing. Typically, these trials include giving an extremely small treatment dosage to 15 or fewer participants.

Phase II Trials

Any trial that moves to the second phase will see an increase in participants. Several hundred people may be recruited for phase II trials.

These trials can last up to two years, with the goal being to test a drug or device on a larger group of people. It also presents an opportunity to learn more about side effects and confirm a treatment’s effectiveness.

Finally, it gives researchers the chance to find the optimal dose for pharmaceutical treatment. According to the FDA, 33% of trials will continue through the clinical trial phases flow chart.

Phase III Trials

Treatments that make it to phase three will have their effectiveness, safety, and side effects further evaluated. It is also when the treatment may be directly compared with existing treatments if they exist.

Researchers will initiate a double-blind design to eliminate any bias in these trials. In other words, neither the participant nor the investigator is aware of who has received a drug or placebo.

Phase III trials can last anywhere from one to four years and incorporate up to 3,000 participants. The FDA will typically demand the completion of one or more phase III trials before considering any treatment for approval.

Approximately 25-30% of trials will qualify for phase IV trials.

Phase IV Trials

Phase IV trials mark the observational or registry stage. The treatment has likely already been approved by the FDA. Patients who receive this new drug will consent to be followed, monitored, and studied through questionnaires or other means.

Researchers can verify how long a treatment works and uncover any side effects that may not have appeared during earlier phases of the clinical trial.

5 Reasons to Enroll in a Clinical Trial

How are participants chosen for a clinical trial?

It all begins by encouraging people to come forward and give their consent to participate. Clinical trials are highly beneficial for you, others, and future generations. Without clinical trials, healthcare would come to a standstill.

1. You Are Needed

The first reason to enroll in a clinical trial is that people like you are necessary. Researchers need people of all ages from all backgrounds. The greater the diversity within a trial, the more accurate the results.

Particularly in later phases of trials, thousands of people may be required to participate in a trial to acquire legitimate, reliable results.

2. You Gain Access to Cutting-Edge Treatments

Patients already undergoing treatments for serious diseases can enroll in a trial to access development stage therapies that would otherwise take years to enter the mainstream healthcare system.

While there are no guarantees that a drug or device tested will help you or even do anything at all, there is always that chance.

3. You Are Helping Future Generations

Another reason to participate in a clinical trial is to help future generations. For example, cancer treatments have come a massive distance since forty or fifty years ago. Countless diseases that were once considered otherwise incurable now have treatments.

Every approved treatment for every disease that appeared was developed through clinical trials. Driving science forward and potentially contributing to saving thousands of lives is your reward for participating in a trial.

4. You Have Security

People are naturally concerned about their symptoms when entering a trial. Clinical trial safety is tightly controlled. You will be continually monitored by a team of experts, ensuring your security.

Your treatment will be fully guided. You will also be able to ask questions and develop a close relationship with the research team behind the trial.

Moreover, the protections in place within modern clinical trials have made participating in these trials safe.

5. You Can Be Rewarded

Existing patients often enroll in trials to potentially find a cure for their illness. Healthy members of the public can also participate in trials. Some clinical trials may come with monetary compensation depending on the perceived risks or time commitment.

While definitely not the primary motivator for entering a clinical trial, receiving a small reward for your efforts is a great way to thank people for choosing to help others.

What to Expect During a Clinical Trial

Anyone looking to enroll in a clinical trial may be wondering what it entails, and the process trials follow.

The number one aspect to remember is that a trial specialist and your physician will remain in constant contact before, during, and after the trial. They are required to ensure all participants fully understand everything going on.

Participants will typically take several tests to confirm their health. Examinations could include an electrocardiogram or blood tests. Any potential symptoms and side effects will be reviewed throughout the trial.

Patients will also need to fill in questionnaires detailing their experiences and how they feel. This data will eventually be used in a trial to ascertain whether a treatment is safe and effective.

Understand that clinical trials are 100% voluntary. Consenting to join a clinical trial does not require completion. Participants are free to withdraw at any point for any reason.

People who withdraw may be given ongoing care to ensure they remain in good health.

Finally, be aware that no trial is 100% safe, especially during the earlier phases. While researchers make every effort to protect their participants, preclinical experiments can only tell scientists so much. Occasionally, serious side effects can occur while participating in a clinical trial.

Next Steps: What to Do If You’re Interested in a Clinical Trial

The first step to uncovering trials in your area is to look them up online. Vial is a service that enables you to find different trials in your area. Trial sponsors will typically release details of their trials publicly. Trial eligibility depends on how specific investigators are on the profile of patients required for the trial.

For example, suppose a new cancer drug is being tested to ease the side effects of chemotherapy. In that case, participants will be limited to people already undergoing chemotherapy or will imminently begin treatment.

To enter a trial, patients must sign an Informed Consent Form. These official documents detail the study and highlight the risks of participating while also indicating the expected benefits.

An Informed Consent Form will also include any financial obligations participants may incur by joining the trial.

Some of the common questions patients might have include:

  • What is the purpose of this trial?
  • Are there any potential benefits to the trial?
  • Which preclinical or clinical tests have been conducted on this treatment?
  • What potential side effects should I be aware of?
  • Do I need to pay anything to receive these treatments?
  • Who will be responsible for monitoring my health during the trial?
  • If the trial is successful, will I be able to continue receiving the therapy after it ends?

Note that delivering an Informed Consent Form and asking questions provides no obligation to participate in the trial. Anyone can withdraw their consent to participate at any point.

Most trials typically have long application periods, so patients are free to take some time to consider their decision before the trial begins.

What matters is that you are entirely comfortable and consent to participating in any clinical trial phase, should you decide to enter a trial.


Joining a clinical trial in a location near you is an opportunity to help future generations. If you are ready and willing to contribute to the future of medicine, look up a clinical trial in your area with Vial.

Skin trials and other clinical trials are integral to the future of healthcare. Without willing participants in clinical trials, it is impossible to test new treatments properly before they go forward for approval. The FDA requires almost all new medical treatments to go through a minimum of three phases of testing before they consider approval.

If you have any questions about clinical trials, contact Vial.

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