Stopping a Clinical Trial: What to Ask

This page is for people thinking about leaving a clinical trial, or told their part in one is ending. It explains your rights, what "stopping" can mean, and what to ask first.

Federal research rules require that the consent form tell you this in writing. Under 45 CFR 46.116, every consent document must state that "participation is voluntary, refusal to participate will involve no penalty or loss of benefits to which the subject is otherwise entitled, and the subject may discontinue participation at any time without penalty or loss of benefits to which the subject is otherwise entitled."

Read the last part again. Leaving the study does not cost you the care you would otherwise get. Your oncologist does not stop treating you. The National Cancer Institute (NCI) says the same thing plainly: "You do not have to continue just because you sign this consent today."

Signing is not a contract to finish. It is permission to begin.

Be precise, because the study team will treat these differently.

You stop the study treatment but stay in the study. The Office for Human Research Protections (OHRP) calls this leaving "the primary interventional component" while allowing other research activities to continue. You come off the drug, but the team keeps collecting scans, labs, or questionnaires.

You withdraw from everything. No more study treatment, no more study visits, no more data collection going forward.

The team takes you off. Protocols list reasons a person must come off study, and these are decided by the rules, not by anyone's opinion of you.

OHRP tells investigators to ask you which one you mean. Say which one, and put it in writing, even if only in an email or the patient portal.

Each study lists its own reasons for taking someone off treatment. Ask the team for the list before you start, or now. Being taken off a study is a rule being applied, not a judgment of you.

Trials can also end for everyone. Under NIH policy, many trials are watched by a Data and Safety Monitoring Board. This is an independent group of experts who see the accumulating data that you and your doctor do not. The board can "make recommendations to the IC, IRB, and investigators concerning continuation or conclusion of the trial(s)." NIH says such a committee is usually there "to recommend conclusion of the trial when significant benefits or risks have developed or the trial is unlikely to be concluded successfully."

So a trial that stops early can mean three very different things: the new treatment is working so clearly that the comparison is no longer fair, it is clearly not working, or something harmful turned up. If your trial closes early, ask which of the three it was. The answer changes what you should do next.

This surprises people. You can stop future data collection. You generally cannot pull back what has already been recorded.

FDA is direct about it: "already-accrued data, relating to individuals who cease participating in a study, are to be maintained as part of the study data." FDA's guidance covers people who stop on their own, are withdrawn by a representative, or are taken off by the investigator.

Rules for research that FDA does not regulate can differ. Ask the study team in writing what will happen to your data and any samples. Do not assume they can be destroyed.

Even if you are done with the treatment, the study still wants to know how you are. OHRP asks investigators to explain "the importance of obtaining follow-up safety data about the subject" when someone withdraws.

Ask the team why follow-up matters in your study. If you are willing to stay in safety follow-up while stopping the drug, say so. Ask how many visits it is and how long the window runs.

Sometimes people stop the trial but want the drug. Two federal pathways exist, and neither is a promise.

Expanded access, sometimes called compassionate use, is a route to an investigational product outside a trial. FDA requires all five of these: a serious or immediately life-threatening disease, no comparable or satisfactory alternative therapy, that "patient enrollment in a clinical trial is not possible," that "potential patient benefit justifies the potential risks," and that supplying the product "will not interfere with investigational trials." Your doctor requests it, and an IRB is involved.

Right to Try is a separate law. The drug must have completed Phase 1, still be unapproved, have an active investigational new drug application, and not be on clinical hold. You must have a life-threatening condition, have tried approved options, and be unable to join a trial. Note two things: "FDA does not review or approve requests for Right to Try Act use," and the law "does not require a sponsor to provide an eligible investigational drug to an eligible patient." The company decides.

Tell the research team before you stop, not after. Ask whether your study drug needs any special steps when you stop, such as a final visit, tests, or returning unused drug.

Also ask about timing. Your next therapy, whether standard or another trial, may require a break after the last study dose. Ask how long yours is before you set a stop date.

• Am I stopping the treatment only, or the whole study, and what does each option mean here?
• What exactly would take me off this study, and has any of it happened yet?
• Will you keep me in safety follow-up, and for how long?
• What happens to my data, and to any tissue or blood samples I gave?
• Is there any route to keep receiving this drug, and are you willing to request it?
• Do I need to taper, return unused drug, or come in for a final visit?
• How long is the washout before my next treatment can start?
• Who prescribes and orders my scans from here, you or my regular oncologist?
• Will I still be told the trial results, and how?

• Electronic Code of Federal Regulations — 45 CFR 46.116, General requirements for informed consent.
• HHS Office for Human Research Protections — Guidance on Withdrawal of Subjects from Research.
• U.S. Food and Drug Administration — Data Retention When Subjects Withdraw from FDA-Regulated Clinical Trials.
• National Institutes of Health — NIH Policy for Data and Safety Monitoring.
• U.S. Food and Drug Administration — Expanded Access.
• U.S. Food and Drug Administration — Right to Try.
• National Cancer Institute — Understanding Cancer Research Consent Forms.

Helpful next pages include What Happens After a Clinical Trial Ends?, How Is Your Safety Protected in a Clinical Trial?, Clinical Trial Results: What They Mean, Making Treatment Decisions in Advanced Cancer, Clinical Trial Visit Schedule: What to Check, Finding Clinical Trials After Standard Options.