Informed consent is one of the central ethical and legal pillars of clinical research. It describes the process by which a trial subject voluntarily provides consent to participate in a clinical trial based on complete, comprehensible information. The requirements for informed consent are enshrined in EU Regulation 536/2014 (CTR), the ICH E6(R3) Guideline for Good Clinical Practice, and the Declaration of Helsinki. Clinical trials conducted without valid informed consent violate fundamental ethical principles and may result in rejection of marketing authorization applications as well as severe sanctions by authorities such as the EMA, BfArM, or FDA.
Legal and Ethical Foundations
Informed consent is not merely a signature but a continuous process of information and dialogue. According to Article 29 of EU Regulation 536/2014, consent must be provided in writing, dated, and personally signed. If written consent is not possible, oral consent may be obtained in justified cases before independent witnesses. The competent ethics committee reviews the consent documents as part of the approval procedure and evaluates in particular the comprehensibility of the patient information.
The ICH E6(R3) guideline specifies that informed consent confirms a person’s voluntary decision to participate in a trial after being informed about all relevant aspects of the study. This includes the objective, duration, procedures, expected benefits and risks, alternative treatment options, and the right to withdraw from participation at any time without providing reasons.
Components of Patient Information
The Informed Consent Form (ICF) typically consists of two parts: the Patient Information Sheet and the actual consent declaration. The patient information must be written in a language understandable to the trial participant and at a level appropriate to their educational background. Regulatory-mandated content includes:
- Purpose and background of the study
- Study design, randomization, and blinding
- Description of all study procedures including invasive measures
- Foreseeable risks, discomforts, and inconveniences
- Expected benefit for the participant or society
- Available alternative treatments
- Provisions for confidentiality and data protection in accordance with GDPR
- Compensation and reimbursement of expenses
- Contact details of the investigator and ethics committee
- Voluntary nature of participation and right of withdrawal
Special Requirements for Vulnerable Groups
Heightened requirements apply to vulnerable populations. Minors cannot provide legally valid consent—in such cases, consent from legal representatives is required, along with age-appropriate assent from the child whenever possible. For persons with limited capacity to consent, such as due to dementia or unconsciousness, Articles 31 and 32 of CTR 536/2014 regulate the conditions for proxy consent. The Principal Investigator is responsible for ensuring that the consent process complies with regulatory requirements.
eConsent, Re-Consent, and Consent Management
The digitalization of clinical trials has introduced the concept of eConsent. Electronic consent systems enable the use of multimedia educational materials such as videos, interactive graphics, and quiz elements for comprehension verification. The EMA and FDA have published guidance documents on eConsent that define minimum requirements for data security, authentication, and audit trail. The use of eConsent does not exempt from the substantive requirements for information provision—the complete informed consent discussion remains mandatory.
If study-relevant information changes after initial consent, a renewed consent process (re-consent) is required. Protocol amendments, new safety information from monitoring by the Data Safety Monitoring Board (DSMB), or modified study procedures may trigger re-consent. The sponsor is obligated to inform the investigator immediately of new findings that may affect the safety of trial participants or the conduct of the study. Consent documentation must be completely archived in the Trial Master File (TMF). During Source Data Verification (SDV), the clinical monitor reviews the completeness and currency of all consent documents as critical data points—missing or outdated ICFs are among the most common GCP findings during inspections by authorities such as the EMA or BfArM.
Frequently Asked Questions
Can a trial participant withdraw consent?
Yes, at any time and without providing reasons. Withdrawal of consent must not result in any disadvantages for the participant regarding their further medical care. Data already collected may—depending on the provisions in the ICF—continue to be used. The withdrawal must be documented and filed in the TMF.
Who is responsible for conducting informed consent?
The Principal Investigator or a qualified investigator authorized by them is responsible for the consent process. The delegation must be recorded in the delegation log. The informing physician must allow sufficient time for questions and ensure that the participant has understood the information before signing.
What distinguishes informed consent from the Informed Consent Form?
Informed consent refers to the process of obtaining informed consent, i.e., the entire information and approval procedure. The Informed Consent Form (ICF) is the specific document containing the patient information and consent declaration that is signed by the participant. Valid informed consent always requires a complete information process—the signature on the ICF alone is not sufficient.
Regulatory References
- EU Regulation No. 536/2014 (CTR), Articles 28–35: Protection of Trial Subjects and Informed Consent
- ICH E6(R3): Guideline for Good Clinical Practice, Section 4.8: Informed Consent of Trial Subjects
- Declaration of Helsinki (WMA, 2013), Paragraphs 25–32: Informed Consent
- GDPR (EU) 2016/679, Article 9: Processing of Special Categories of Personal Data
- EMA Guideline on Computerised Systems and Electronic Data in Clinical Trials (2023)