Informed Consent in Clinical Trials: A Continuous Process, Not a Signature

At a glance

• Consent is a process, not a form. The signature documents it; the conversation, the comprehension, and the freedom to decline are the thing being documented.
• It has to be obtained before any study procedure, freely given, and free of coercion or undue influence. That is a hard floor in both ICH E6(R3) and US regulation.
• The consent form must carry defined content: the basic elements of informed consent, plus additional elements where they apply.
• It does not end at signing. New information that could change a participant’s willingness to continue triggers a reassessment and, where needed, re-consent.
• Electronic consent is acceptable on the same terms as paper, provided the electronic record and signature meet 21 CFR Part 11.

Consent is a process, and the signature is its receipt

The most common conceptual error in consent is treating the signed form as the event. The regulations treat the form as evidence that a process happened. ICH E6(R3) frames it as the first of its principles: freely given informed consent should be obtained and documented from every participant prior to clinical trial participation (ICH E6(R3), Principle 1). “Obtained and documented” are two acts. The obtaining is a conversation in which a participant is informed and given a real chance to decline; the documenting is the signature that records it.

US regulation sets the same floor in operational terms. No investigator may involve a human being as a subject in research unless the investigator has obtained the legally effective informed consent of the subject or the subject’s legally authorized representative, and shall seek that consent only under circumstances that provide sufficient opportunity to consider whether to participate and that minimize the possibility of coercion or undue influence (21 CFR Part 50 §50.20). Two operative phrases there carry weight: “sufficient opportunity to consider” rules out rushing someone into a decision, and “minimize coercion or undue influence” rules out pressure, including the subtle pressure of a treating physician asking their own patient.

Before any procedure, by qualified staff, voluntarily

The sequence is firm. Consent comes first. ICH E6(R3) provides that prior to trial participation the informed consent form should be signed and dated by the participant or by the participant’s legally acceptable representative (ICH E6(R3) §2.8.7). A study procedure performed before consent is a deviation, and usually an important one.

Who runs the conversation matters too. The informed consent process should be conducted by the investigator or other investigator site staff delegated by the investigator, in accordance with applicable regulatory requirements (ICH E6(R3) §2.8.5). And the voluntariness requirement is explicit: neither the investigator nor the investigator site staff should coerce or unduly influence a participant to participate or to continue their participation (ICH E6(R3) §2.8.3). Voluntary means voluntary at every point, not just at the first signature.

What the form must contain

A consent form is not free text. 21 CFR Part 50 §50.25 defines the basic elements of informed consent and the additional elements that apply where relevant (21 CFR Part 50 §50.25). The basic elements cover the essentials a person needs to decide: that this is research, its purpose, the procedures, the foreseeable risks and benefits, the alternatives, confidentiality, compensation and treatment for injury, who to contact, and that participation is voluntary and can be stopped without penalty. The additional elements address situations such as unforeseeable risks, circumstances under which participation may be ended, and consequences of withdrawal. A form missing applicable elements is non-compliant even if signed.

ICH E6(R3) ties the documentation to the comply-with-regulations duty directly: in obtaining and documenting informed consent, in paper or electronic format, the investigator should comply with the applicable regulatory requirements (ICH E6(R3) §2.8.1). And the US documentation rule is specific: informed consent shall be documented by the use of a written consent form approved by the IRB and signed and dated by the subject or the subject’s legally authorized representative at the time of consent (21 CFR Part 50 §50.27). At the time of consent is the phrase that defeats back-dating.

It does not end at signing: re-consent

Because consent is ongoing, it can become stale. ICH E6(R3) builds in the trigger: new information that could impact a participant’s willingness to continue participation should be assessed to determine if re-consent is needed, and where it is needed, the new information should be clearly identified in the revised informed consent materials (ICH E6(R3) §2.8.2). The classic case is an emerging safety signal. A participant who consented under one risk picture has a right to decide again under a new one. Re-consent is not a paperwork refresh; it is the same voluntariness principle applied to changed facts.

Electronic consent: same standard, electronic form

eConsent is permitted, and it does not lower the bar. ICH E6(R3) explicitly contemplates consent in paper or electronic format (ICH E6(R3) §2.8.1). For US studies, the equivalence runs through 21 CFR Part 11: FDA considers electronic records to be equivalent to paper records and electronic signatures to be equivalent to handwritten signatures when they meet the requirements under Part 11, subject to specific exceptions (FDA Electronic Systems in Clinical Investigations guidance, background). So an electronic consent record is acceptable when the system delivers Part 11 controls, including the secure, computer-generated, time-stamped audit trail that 21 CFR Part 11 §11.10(e) requires to record actions that create, modify, or delete electronic records. The process duties do not change: the participant still needs comprehension, voluntariness, time to decide, and the chance to ask questions. eConsent changes the medium of the receipt, not the substance of the consent.

Emergencies and representatives

There is a narrow path for emergencies. In emergency situations, when prior consent of the participant is not possible, ICH E6(R3) provides that the consent of the participant’s legally acceptable representative, if present, should be requested, and that the participant or representative should be informed about the trial as soon as possible and consent requested as appropriate, in accordance with the processes approved by the IRB/IEC (ICH E6(R3) §2.8.8). This is an IRB-governed exception, not a convenience. Where a legally acceptable representative consents, the consenting and re-consent activities apply to that representative.

Comprehension is part of the standard, not a courtesy

Consent that is rushed is not consent, and the guideline says so structurally. Before informed consent may be obtained, the investigator or investigator site staff delegated by the investigator should provide the participant ample time and opportunity to inquire about the details of the trial and to decide whether or not to participate (ICH E6(R3) §2.8.6). “Ample time and opportunity to inquire” is a process requirement, not a nicety. A consent visit scheduled with no room for questions, or held under the implicit pressure of a procedure already booked, fails it regardless of what the signed form looks like afterward.

The standard also reaches the participant who cannot read it. If a participant or the participant’s legally acceptable representative is unable to read, an impartial witness should be present, remotely or in person, during the informed consent discussion (ICH E6(R3) §2.8.9). The witness is there to attest that the information was accurately explained and apparently understood, and that consent was freely given. This is the same principle running through the whole topic: the regulation cares about whether the person actually understood and freely agreed, and it builds in safeguards for the situations where comprehension is most at risk.

That emphasis on comprehension shapes how the content elements should be used too. The basic and additional elements that 21 CFR Part 50 §50.25 requires are not a script to read at someone; they are the information a person needs to make a real decision, and the obligation is to convey them in a way the participant can understand. A technically complete form delivered in language the participant cannot follow satisfies the letter of the elements while defeating their purpose. The through-line from the legal floor to the witness rule to the comprehension expectation is consistent: documentation proves consent happened, but the thing being documented is a genuine, informed, voluntary decision, and every one of these provisions exists to protect that decision rather than the paperwork around it.

Where teams get it wrong

• Treating the signature as the event. The signature documents a process. An inspector asks how the conversation happened, not just whether a name is on the line.
• Procedure before consent. Any study-specific procedure before a signed, dated consent is a deviation. Screening that requires consent must wait for it.
• A form missing applicable elements. §50.25 elements are not optional. A signed form that omits an applicable element is still non-compliant.
• Skipping re-consent on new safety information. A material change in risk triggers reassessment under §2.8.2. Continuing on stale consent is a finding.
• Assuming eConsent is lighter. It carries the full consent process plus Part 11 controls, not fewer obligations.

Consent done well looks like a decision a participant made with enough information, enough time, and no pressure, documented at the moment they made it and revisited when the facts change. The form is the proof, never the point.

Sources

• ICH E6(R3) Good Clinical Practice, version R3
• 21 CFR Part 50, Protection of Human Subjects (2024)
• 21 CFR Part 11, Electronic Records; Electronic Signatures (current as of 4/14/2026)
• FDA, Electronic Systems, Electronic Records, and Electronic Signatures in Clinical Investigations: Questions and Answers (2024)