Phase I Clinical Trials for Cancer Treatment

Approved by the Cancer.Net Editorial Board, 03/2016

Listen to the Cancer.Net Podcast: Phase I Clinical Trials, with Jeffery S. Weber, MD, PhD, adapted from this content.

Phase I clinical trials are the first opportunity for doctors to test a new cancer drug or treatment in people. The U.S. Food and Drug Administration (FDA) requires that all potential cancer treatments undergo testing. For each drug or therapy, testing looks at the following factors:

  • Safety

  • Dose

  • How often the drug or therapy should be given

  • How long treatment should last

  • How well it can treat a specific type of cancer

Often doctors combine a new drug with standard treatments, such as other drugs or radiation therapy. Or, if early results seem promising, doctors may combine phases I and II to include many more people. The research community calls this a phase I/II clinical trial. Based on phase I/II trials, the FDA has recently approved several drugs or drug combinations that are benefitting patients today.

Learn more about drug discovery and development and clinical trial phases.

Why today’s phase I studies are different

In the past, the main way doctors treated or controlled cancer was by using chemotherapy. This type of treatment stops new cancer cell growth, but often hurts healthy tissue. It was important for doctors to carefully watch how much of these drugs they gave to patients. If the doses were too low, there was little chance that the drug could treat the cancer. However, high doses of these drugs might get rid of the cancer, but cause dangerous side effects.

Today, many new cancer drugs are either immunotherapy or targeted therapies:

  • Immunotherapy is a type of cancer treatment designed to boost the body's natural immune defenses to fight the cancer. Learn more about immunotherapy.

  • Targeted therapies target the cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. Doctors can test a patient’s tumor for those genes or proteins, which are called tumor markers. Some doctors call them “drivers” because they drive the growth and spread of the cancer. Examples are KRAS, ALK, and BRAF genes. Testing a patient’s tumor tissue helps doctors learn more about the cancer. It also helps them learn whether patients might benefit from a specific targeted therapy. Learn more about targeted therapy.

Different study designs for clinical trials have improved how quickly doctors can learn if a drug works for patients. For example, doctors can find the best dose much faster while also looking at how the drug treats the cancer.

Why choose a phase I clinical trial

New drugs tested in phase I clinical trials often shrink tumors and benefit patients. The drugs can also stop the cancer from growing and getting worse. Some recent examples include:

  • Pembrolizumab (Keytruda) for people with metastatic melanoma

  • Crizotinib (Xalkori) for people with ALK-positive lung cancer

Many patients feel like they’re taking control of their cancer care when they’re part of a clinical trial. And of course, many patients want to help other people with cancer by being in a clinical trial.

Also, people in phase I clinical trials report:

  • A high quality of life

  • Satisfaction with their medical care

  • Management of pain and other symptoms

Most health insurance plans now cover routine medical costs for people in clinical trials. However, there are cases where they don’t. Learn more about health insurance and clinical trials.

The truth about phase I clinical trials

Many people think that clinical trials, especially phase I trials, aren’t an option until they try all other options. In fact, clinical trials are always a treatment option. Sometimes a clinical trial is as good as or better than standard therapy for some cancers. Often people have more choices to be in a clinical trial the earlier they are in the treatment process.

Some patients would rather get standard treatments because they think phase I trials won’t work. However, research and drug discovery is moving fast. That means the standard treatment may not always be the best option.

As doctors learn more about which drugs treat which cancers best, many patients experience a:

  • Stabilization of the cancer, which means there’s no new growth; or

  • Response from the drug being tested, usually measured as a tumor shrinking or going away.

It’s important to talk with your doctor early on about potential clinical trials. He or she can explain how they compare with the standard treatment for your cancer’s type, stage, and/or subtype.

Questions to ask your health care team or research team

  • What clinical trials are open to me? Where are they being performed and how do I learn more about them?

  • What’s the purpose of this clinical trial?

  • What are the possible risks of being in this clinical trial? What are the potential benefits to me?

  • Why do you recommend this specific clinical trial for me?

  • What other treatment options are available to me?

  • Does this clinical trial include the use of a placebo (an inactive treatment)?

  • What is a biospecimen (tissue sample), and what types does this trial need?

  • What happens to the tissue samples? Do I need to donate them to participate in the study?

  • What tests will the doctor do on the tissue sample?

  • What’s a tumor marker? Will doctors test them in the clinical trial?

  • Who’ll coordinate my overall care if I join the clinical trial?

  • What will it cost me to be a part of this clinical trial?

  • Can you help me find out which costs my insurance covers and which ones I need to pay for?

  • If I’m worried about the costs related to my cancer care, who can help me?

Find additional questions to ask the research team about clinical trials.

More Information

Clinical Trials

Introduction to Cancer Research