What are Phase 1 Clinical Trials and When are They Done?

When are Phase 1 Clinical Studies Done for Cancer?

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If you are considering a phase 1 clinical trial, what exactly does this mean? How does this differ from other phases of clinical trials? With the recent advances in cancer treatment, the role of phase 1 clinical trials is becoming more important. While at one time these trials may have been thought of as "last ditch" efforts, there are now many people who are surviving cancer due to the existence of these trials.

Let's take a look at phase 1 clinical trials within the realm of modern research and discuss why a phase 1 clinical trial may not be as "risky" as in the past.

Keep in mind that the purpose of clinical trials is to find therapies that either work better or have fewer side effects than medications we currently have available. All medications used to treat cancer were once tested as part of a clinical trial. And during that time, the only people who were able to reap the benefits of these treatments were those who were in the clinical trial study group.

Definition and Purpose of Phase 1 Clinical Trials

Phase 1 clinical trials are done to see if an experimental drug or treatment is safe. After a treatment is tested in the lab or on animals, it enters a phase 1 clinical trial that is done with humans. These trials usually involve only a small number of people to determine if a drug or treatment is safe and to determine the best dose of a drug and how it should be given (whether orally or intravenously).

Though the primary purpose of these trials is to evaluate safety, they may also determine if a treatment appears to work for a cancer.

Other Phases

There are three phases of clinical trials that must be completed before a drug is FDA approved. If a treatment appears safe at the end of a phase 1 clinical trial, it may then enter a phase 2 clinical trials, a study done to see if a treatment is effective.

If a drug or treatment is deemed safe in a phase 1 trial and effective in a phase 2 trial, it will then enter a phase 3 clinical trial. Phase 3 clinical trials are much larger and are done to see if a treatment is not only safe and effective but works better or has fewer side effects than treatments currently available.

Phase 1 Clinical Trials Have Changed in the Last Decade

Phase 1 trials, and what you may expect if you are enrolled in one, have changed significantly in just the last few years. Many of the new drugs being tested in 2018 have been carefully designed to act on a precise pathway in the growth of a cancer. Not only are drugs such as these often less likely to have major side effects than traditional chemotherapy drugs (though they can), but based on design there is a more reasonable chance that they will make a difference for your cancer. After all, if you can inhibit a specific step that a cancer must go through to divide (and thus grow and spread), there is a reasonable chance that a cancer that has been shown to be dependent on that step will respond.

In such cases it could be that the only options for treating the cancer would be conventional chemotherapy drugs. Drugs such as targeted drugs are often more likely to hold a cancer in check for some time, and immunotherapy drugs, for a small percent of people at least, may result in a durable response (long-term response).

With the advances in precision medicine, it's likely that phase 1 clinical trials will continue to offer more promise for individuals rather than simply be trials performed to see if a drug is safe.

Thoughts When Considering a Phase 1 Clinical Trial

There are a few reasons someone may consider participating in a phase 1 clinical trial. One is the hope of advancing research that may help others with your disease in the future. Another is the hope that a new drug or procedure that has not yet been tested on humans will offer a chance of survival when other treatments have failed. The only way that advances in cancer treatment, and subsequent survival, are made, is via patient participation in clinical trials.

That said, clinical trials are not for everyone.

Risks and Benefits

It's important to consider all of the risks and benefits of clinical trials if you are considering one of these studies. It's often helpful to write down both the pros and cons of the study on a sheet of paper so you can visibly weigh your options. There is not a right or wrong choice, only the choice that is right or wrong for you.

Other Options for Receiving Experimental Drugs

For the most part, the only way that you can use an experimental (investigational) drug is to take part in a clinical trial. That's not always the case, and some people may qualify for compassionate use or expanded access to drugs not yet approved by the FDA. If you do not qualify for a clinical trial but an investigational drug appears promising for your particular cancer, take a moment to learn about compassionate drug use.

Bottom Line

Phase 1 clinical trials are the first medical studies in which a drug or procedure is tested in humans. While traditionally this has been anxiety provoking and has led to jokes about being a guinea pig, these first studies can be looked at in different ways. From one side they may be more risky. After all, the primary purpose of these trials is to determine if a drug is safe for people (and also to get an idea about the best dose to use).

Yet, from a different angle, a phase 1 clinical trial may have more to offer. Many stage 3 clinical trials compare drugs that have already been looked at. The hope may be that a drug will improve survival if only for a few months. With a phase 1 clinical trial, however, a new drug (and possibly a new category of drugs) is being looked at which may or may not help, but may help more than anything else currently available. Examples of this have been frequent in recent years. Since anxiety remains about being involved in clinical trials, take a moment to learn about the myths about clinical trials and what is fact and fiction.


US Food and Drug Administration. The FDA's Drug Review Process: Ensuring Drugs are Safe and Effective.