Phases of Cancer Clinical Trials – An Introduction, with Neal Meropol, MD

Last Updated: July 3, 2018

Dr. Neal Meropol explains how clinical cancer research is done in distinct segments, called the phases of clinical trials.

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Phases of Clinical Trials

PRE-ACT Video Series for Patients: Preparatory Education About Clinical Trials

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Cancer.Net®: Doctor-Approved Patient Information from ASCO®

Phases of Cancer Clinical Trials: An Introduction

What are Clinical Trials?

Neal J. Meropol, MD, FASCO: Cancer clinical trials which are also called clinical studies are the way we have to find new ways to prevent, treat and diagnose cancer.  All of the treatments that we now consider to be standard today were once tested in clinical trials.  When patients volunteer to be part of a clinical trial they’re taking part in research and on one hand have the opportunity to gain access to a new therapy, a potential treatment that they might not otherwise have access to for themselves and the hope of personal gain.  On the other hand they’re contributing knowledge that will help future cancer patients as well and help us develop the new standards of tomorrow.

As you talk about clinical trials with your doctor you may hear your doctor speak of them in terms of phases, a phase one clinical trial, a phase two clinical trial, a phase three clinical trial.  Each phase of clinical trials has different objectives.

Phase One

Dr. Meropol: A phase one clinical trial is the first time a drug or a combination of drugs are being used in people.  And the goal of a phase one study is to determine the optimal dose and schedule and find out the side effects associated with new treatments.

Phase Two

Dr. Meropol: A phase two clinical trial treats a more homogenous patient population, treats people with a certain disease or certain characteristics of their tumor in order to find out initially does the treatment work against your type of tumor.  That’s a phase two study. 

Phase Three

Dr. Meropol: When discussing a phase three clinical trial you may hear the term randomization, because phase three studies assign patients to the different treatment arms, the different possibilities, the standard therapy or the experimental therapy by chance. A computer program will often make that assignment.  When you choose to take part in a phase three study you are told beforehand what the possibilities are and what the treatment assignments might be.

These are often called randomized clinical trials and they’re the final stage in the development of a new treatment before it seeks approval by the FDA.   In a phase three clinical trial we’re often treating hundreds and sometimes thousands of patients to show that the new treatment is better than the standard.

Where to Get More Information

Dr. Meropol: Clinical trials represent the highest quality cancer care that we can provide and therefore I recommend that all patients discuss the options of clinical trials with their doctors.

One place where you can get excellent patient oriented clinical trial information is on Cancer.Net, has information presented as text that you can read about clinical trials, but also video content about clinical trials to answer the questions that you might have about participating in a clinical trial. 

There is a program on called PREACT, which stands for Preparatory Education Clinical Trails, that you can find at,  p-r-e-a-c-t.  The PREACT program will give you access to a video library that addresses the common questions that people have about participating in a clinical trial.

[Closing and Credits]

Cancer.Net®: Doctor-Approved Patient Information from ASCO®

ASCO's patient education programs are supported by Conquer Cancer Foundation of the American Society of Clinical  

Special Thanks:

Dr. Mary Wilkinson, Dr. Raymund Cuevo, and the staff at Medical Oncology & Hematology Associates of Northern Virginia

Carolyn B. Hendricks, MD, The Cancer for Breast Health

Hasbro Children’s Hospital

Helen F. Graham Cancer Center at Christiana Care Health System

The Adele R. Decof Comprehensive Cancer Center at The Miriam Hospital. The Miriam Hospital is a teaching hospital of The Warren Alpert Medical School of Brown University

Video Footage and photography courtesy of:

St. Jude Children’s Research Hospital Biomedical Communications

Moffitt Cancer Center

University Hospitals Case Medical Center Seidman Cancer Center

The opinions expressed in the video do not necessarily reflect the views of ASCO or the Conquer Cancer Foundation.

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