Editor’s note: Jack Knorr is a Senior Research Scientist supporting Early Phase Immunology at Eli Lilly and Company. One of Jack’s chief responsibilities is communicating key statistical concepts to non-statisticians on his project teams. Jack received a bachelor’s degree in mathematics and a master’s degree in statistics from Oklahoma State University, then obtained his doctoral degree in statistics from Baylor University.
When determining whether a trial is the right choice for you, it’s important to understand your own reasons for participation. If your intention going into a trial is solely to receive a novel treatment or drug, it could be disappointing to learn a trial may have a placebo group. Understanding what placebo is and why it may be used in a particular trial is an important factor in assessing if a trial is right for you. Participants who receive placebo in a study play an essential part in determining the efficacy (power to produce an effect) of a treatment or drug.
What is a Placebo?
In clinical trials, participants may be assigned the drug that is being studied or a placebo. A placebo is something that is supposed to look and behave like the actual treatment but doesn't contain anything that’s meant to affect the person’s health.
Most people think of the stereotypical sugar pill, but a placebo can also be a shot or infusion that's filled with a saline solution.
The point of the placebo is to ensure that everyone in the study is treated the same way with the exception that some people in the study are going to get the drug and some are not.
When conducting trials, it's important to ensure that whatever effect is seen in a drug or intervention can only be explained by the fact that these participants received the actual treatment. To ensure this, all the participants who are enrolled into the trial are treated the exact same way with the sole exception that some received the drug and some received the placebo.
The point of this is that if the group of participants who received the treatment do better in terms of responding to their disease than those on the placebo, principal investigators can attribute the improvement to the drug, rather than some other underlying factor that may be associated with the disease that the participants are going through.
The placebo is important in cases where a lot of the response is self-reported by the participants. Consider a drug that was developed to improve a participant’s headache frequency or intensity. There may be some participants who notice improvement strictly due to attention and care or other physiological factors, even though their treatment was void of anything that would change their condition or make them feel better. This is an example of the placebo effect.
Giving a participant a placebo will not magically make a tumor shrink, meaning that principal investigators only give this in trials when it is ethical to do so. For example, participants will not be given a placebo if there is a risk of death due to lack of treatment.
What Does a Study Participant Need to Know About Placebo?
Placebo is one design element utilized in clinical research. If the study has a placebo component to it, it’s important to be aware that as a participant, there is a chance that you may not see any benefits from the study. Often participants that are assigned to receive placebo may have an opportunity to receive the investigational drug at a different time in the trial. Before determining if a trial is the right choice for you, it’s important to ask questions about the placebo.
Questions to Ask About Placebo
- What are my odds of receiving a placebo?
- If I do get assigned a placebo, how long will I take a placebo for, and is there an opportunity to take the actual study drug later?
- If I get the actual novel drug, or existing drug or treatment, is there a chance that I would get a placebo later?
There's a common study design called a crossover design where a participant will spend a certain amount of time receiving the investigational medicine or placebo. Then after this timeframe, they’ll switch, or crossover, and receive the other one.
The other way to get study drug would be a follow on study (long-term extension or open-label) where all participants may be eligible to enroll after the initial trial.
What Else Should I Know About Placebo?
It’s important to remember that trial participants can stop being a participant at any time. Participants do sign a consent form in the beginning; however, this is not the same thing as a contract. So, throughout their journey, participants have full control over their status in the trial.
Another key point to consider is that depending on the ailment, participants’ exposure to the placebo may vary. For example, some participants in an atopic dermatitis study may receive placebo for 4 months, while those in an Alzheimer's study may be on it for a year.
Also, not every trial has a placebo group. For instance, with oncology, there's rarely a placebo.
Overall, getting a placebo in a study does not mean that it is the only thing you’ll receive during the duration of your trial participation; in some trials you may continue your current treatment and receive placebo or the investigational drug. And placebo or not, every participant is effectively helping to change the way a disease or ailment could be treated in the future.
Consider joining a clinical trial today here.