What is a Phase I Clinical Trial?

Nearly all cancer drugs in use today were developed through clinical trials. But before they are approved for use, they must go through multiple phases designed to test the drug’s safety and efficacy. These phases include preclinical, phase I, II, and III.

Andrew Wolanski, NP
Andrew Wolanski, NP

In phase I clinical trials, investigators evaluate how often and how much of the drug should be given. These early trials are often small, enrolling between 15 and 100 patients, but are an essential step in the development of more effective cancer treatments.

“People who enroll in phase I trials are helping us discover new treatment options for patients in the future,” says Andrew Wolanski, a nurse practitioner with Dana-Farber’s Early Drug Development Center (EDDC), which specializes in conducting phase I clinical trials of experimental drugs for solid tumors. “Without these important trials, many cancer therapies wouldn’t be available today.”

Below are five important questions about phase I trials:

1. What happens during a Phase I trial?

The trial typically begins by giving a low dose of the drug under study to participants with a range of cancers. If there are no serious side effects, another group is given the drug at a higher dose and additional patients join the group until researchers determine the highest safe dose. If there is evidence that the drug has promise for treating cancer, it will be studied in a phase II trial, which is typically directed toward a certain cancer type.

2. How do I enroll in a trial?
The patient’s doctor or oncologist usually refers the patient to a clinical trial, but patients may also reach out to phase I trial doctors directly to set up a consultation. During the consultation, the doctor will discuss the patient’s eligibility for a trial (or several trials) and answer any questions or concerns the patient may have.

3. How do I become eligible for a clinical trial?
The list of characteristics that participants must share may include a specific type and stage of cancer as well as the number and type(s) of cancer treatment already received. Other criteria include age, gender, medical history, and current health status. Criteria may also be assessed through blood tests, skin or tumor biopsies, MRIs, or CT scans.

4. What happens when I join the trial?
Before starting on the trial, a patient will be asked to sign consent forms. He or she will be assigned to a team of experts in medical oncology, nursing, and clinical research who work together to ensure that the patient’s treatment is closely monitored and safe. In most studies, the patient will need to come into the clinic regularly for blood tests and other procedures. Some will be quick visits (one to two hours), while others may be much longer (10-12 hours).

Geoffrey Shapiro, MD, PhD
Geoffrey Shapiro, MD, PhD

5. How do I find out about available clinical trials?

In addition to being referred by a doctor or oncologist, patients can check a list of Dana-Farber clinical trials here, or a national list at clinicaltrials.gov.

“Phase I trials involve a high level of complexity and detail,” says Geoffrey Shapiro, MD, PhD, director of the EDDC. “We approach things optimistically and try to help as many people as possible.”

Dana-Farber’s Early Drug Development Center currently has more than 70 phase I clinical trials open to patients. For more information, visit the EDDC website. For a full list of clinical trials at Dana-Farber, visit this page.

2 thoughts on “What is a Phase I Clinical Trial?”

  1. It would be nice to know what percentage of drugs get out of Phase I and go on to Phase II and also Phase III in the U.S.

    • Dear Berdj –

      Thank you for your question and for reading Insight. Please see the below response from our team at the Early Drug Development Center:

      Three-quarters of investigational drugs for cancer are deemed safe for testing of effectiveness and progress from phase I to phase II. Around 40% of cancer drugs that undergo phase II efficacy testing move on the phase III. Of those drugs that reach phase III, about 47% make it to submission of an application for marketing approval to the FDA. Overall, about 13% of drugs tested in phase I are eventually approved for clinical use. Success rates vary by indication as well as type of compound.

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