Clinical trials are carried out by drug developers to assess the safety, dosing and efficacy of new drugs and medical devices in humans. During the course of a study, participants may experience one or more adverse events (AEs), which may include unintended symptoms or medical issues.

In some cases, AEs may be relatively mild, such as a headache or an abnormal lab test result that has no clinical significance and thus requires no medical intervention. However, others may be more serious, such as metabolic or cardiovascular complications, bleeding, infection or other conditions that could require hospitalization or cause death. Depending on their severity, some AEs may need to be reported to regulatory authorities immediately and may cause the trial to be paused or halted.

Typically, the trial sponsor collects information about AEs from individual trial investigators, and shares the findings with other investigators at other trial locations. The short-term goal is to protect the safety and wellbeing of the patient volunteers. The long-term goal is to develop the most comprehensive safety profile and dosing strategies for the new drug or device, to comply with the regulatory review process, and to inform prescribers in clinical practice. 

Once the medication is being used in actual clinical practice, the ongoing data collection of AEs experienced in real world clinical practices is referred to as post-marketing surveillance. Such findings help to inform the safest prescribing practices — especially with regard to patient groups that were not adequately represented in the clinical trial itself. The U.S. Food and Drug Administration (FDA) provides guidance on how adverse events must be reported.

If a new drug or device is approved by the FDA, the AE data collected from participants during the clinical trial process are used to establish the side effect profile of the drug. Side effect profiles are the list of potential side effects and warnings described in the drug package insert or heard on drug commercials. 

Capturing AEs

In some cases, information related to AEs is objective, meaning it can be directly measured or observed. Examples of objective AEs are lab results, events diagnosed through imaging such as stroke or heart attack, and rash. 

However, in other cases, information related to AEs is more subjective, or cannot be directly measured. Subjective AEs, like headache, nausea, itchiness, or pain, are only captured when participants report them. The single best tool for evaluating subjective AEs is the clinical interview. With no standard framework in place today to ensure that AEs are consistently and properly identified and recorded, there is a lot of opportunity for relevant safety signals to be missed.

Information solicited from participants varies greatly with how investigators frame their questions to trial participants. Inexperienced or poorly trained interviewers may introduce bias, or contribute to inconsistent findings. Participants themselves may not recognize the importance of something they have been experiencing, and thus they may not think to report it on their own.

For instance, rather than just asking open-ended questions such as “how are you feeling?” or “have you experienced any changes since our last visit?” investigators may ask detailed questions or present checklists of potential symptoms or adverse events. For the participant, this may seem overly repetitive, redundant, or time-consuming to go through an exhaustive list of questions during every encounter. However, participants who report AEs during the trial are providing an invaluable contribution to the safety of everyone who is prescribed the drug or device after it is approved. 

Research professionals are working to reduce the burden of AE assessments on participants with technology, such as apps for participants to easily report AEs as they occur, and more patient-centered schedules for assessments such as labs and physical exams. 

This blog is intended to be informational in nature. The information and other content provided in this blog, or in any linked materials, are not intended and should not be construed as medical advice, nor is the information a substitute for professional medical expertise or treatment.

If you have any questions or concerns, please talk to your doctor. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog or in any linked materials. If you think you may have a medical emergency, call your doctor or emergency services immediately.

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