The first trials of a new drug performed in humans are known as Phase I studies; they test the safety of the treatment. These studies may also look for early signs of effectiveness, such as viral load reductions after the drug is taken for one or two weeks.
Once Phase I studies are completed, the drug moves into Phase II testing. These studies collect safety and dosing information and begin to see how effective the treatment is when taken for several months.
Phase III studies are larger, longer trials designed to confirm the proper dose, whether or not a treatment works and whether there are important safety issues.
The U.S. Food and Drug Administration (FDA) will review data from all of the trials, along with test tube and animal studies, to determine whether or not to approve the drug. Sometimes, an important new drug is granted “accelerated approval” by the FDA while the Phase III studies are still ongoing. Other times, the FDA requires all studies to be completed before an application for approval can be filed.
Finally, Phase IV studies may evaluate the approved drug in more people and different populations. Phase IV studies, also known as post-marketing studies, are also conducted to test several different approved treatments, to find out if one works better than others.
Unfortunately, some people living with viral hepatitis enter clinical trials to gain access to a doctor or clinic because they may not have any other options for receiving care. Some trials provide the equivalent of free care and medication, but some do require that certain tests be covered and that approved meds be provided by the participant. Although enrolling in a study may be a useful part of your treatment, it is important to know that the main purpose of the trial is to test the treatment—not to provide the best possible medical care. Therefore, study participation is not a good substitute for regular doctor visits.
Most, though not all, clinical trials compare at least two different drugs or drug regimens. Many of these studies may have one arm, or group, of people taking a drug regimen that contains at least one experimental drug. They will likely be compared with a “control group”—people living with viral hepatitis receiving the approved standard of care (for example, pegylated interferon plus ribavirin).
Another type of control found in clinical trials uses what is known as a placebo—a fake, sugar or dummy pill—that contains no medicine but looks exactly like the tested treatment. Today, clinical trials for viral hepatitis rarely use control arms in which only a placebo is given. This is because we already have effective treatments—as a result, an experimental drug or regimen needs to show that, when compared with regimens already available, it works at least as well, causes fewer side effects, may not need to be taken for as long, or is easier to take.
When studies compare different medicines, a computer may be used to randomly assign you to one of the treatment arms. This is known as randomization. This is important, as it prevents the researchers conducting the study from being biased—for example, assigning patients they already have a relationship with to receive the experimental treatment and those they don’t know to receive a placebo.
Additionally, you may not be told which treatment you are receiving. This is known as a blinded study: Participants don’t know whether they are in the control arm or in the arm receiving the experimental treatment. When both the study participants and the doctors don’t know who is in the control group, the study is called double-blind, again to prevent clinical trial staff members from being biased.
The government usually tries to carefully regulate clinical trials. The information in this Hepmag lesson is specific to the United States. However, most developed countries offer similar regulations for clinical trials.