Clinical trials are research studies that closely monitor participants to test new interventions or drugs that may prevent, stop or treat diseases, including Alzheimer’s. All clinical trials end, and while the early termination of a trial may cause strong emotions in participants, it’s important to understand that researchers have gathered important data even if the results aren’t positive.

Why trials end

Researchers develop a plan, called a protocol, for a trial before it begins. The protocol includes how long the study will last. A trial may be stopped early, however, for a number of reasons:
  • Finding of benefit: Researchers may find that a treatment shows early positive results, so the trial may be terminated in order to share the findings sooner. Sometimes, participants receiving a treatment experience results that are clearly better than the participants in the control group that doesn’t receive the treatment; researchers may then decide it’s unfair to continue the study.
  • Safety concerns: Researchers may learn that an intervention is potentially unsafe and will discontinue the trial to protect participants.
  • Futility: Researchers sometimes do an analysis during a study and predict outcomes. A trial may end early if the analysis shows futility, which means the results are so unfavorable that it makes sense to stop the trial.
  • Business reasons: A pharmaceutical company might decide to reprioritize its resources and discontinue a trial in favor of focusing on the testing of a different drug.  

Notifying participants

All trial participants are notified of important changes to their study. This process can be complicated when a trial ends early.

Trials have organizations that are sponsors in charge; for example, a drug company. A legal requirement may exist that the sponsor must communicate the decision quickly and publicly to its shareholders, most frequently via a press release. Until they take this step, the study sponsor isn’t allowed to share the information with anyone, including the study sites (medical centers conducting the study), study teams (researchers working with participants) and trial participants.

A trial participant may learn a study ended early from news coverage or social media rather than the study team. Before the trial begins, it’s a good idea to ask how updates will be shared.

Emotions when a trial ends

It’s normal to feel a range of emotions after the discontinuation of a clinical trial. If a trial ends early because of positive results, you may feel relieved or satisfied. If a trial ends early due to unfavorable results or safety concerns, you may feel sad, disappointed, afraid, vulnerable or worried about what will happen next.

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All clinical studies — even unsuccessful ones — help scientists learn. Everything we know about current and potential Alzheimer’s treatments has come from clinical trials, including those that didn’t meet their intended outcomes. It may be helpful to ask the study team what they learned during the trial and why it ended early.

Possible questions include:
  • Why did the trial end?
  • What were the results?
  • What are the next steps for this treatment or intervention?
  • Can you share my personal results?
  • Which group was I in? Did I receive the study treatment? Was I in the control group?
  • Can I still receive or continue to receive the study treatment even if the trial has ended?
  • Were there side effects during the trial? If the answer is yes, what does that mean for me personally? Did I experience side effects?
  • Are there other opportunities for me to participate in another trial?
  • Where can I go for support? Can I talk with my doctor about the trial or is the information confidential?
  • Whom do I contact if I have additional questions?
It can be a good idea to get information and support from someone you trust, such as a family member, friend, doctor or faith leader. You can also call the Alzheimer’s Association 24/7 Helpline at 800.272.3900.

Before you sign up

Ask the study team questions before you sign up for a trial. This helps ensure you’ll understand the process and know what to expect, even if a trial ends early.

Possible questions include:
  • If there’s news about the trial, how will I be notified?
  • Will you tell me the results of the trial? Will you tell me my personal results? If so, when?
  • Will you tell me if I received the study treatment or if I was in the control group?
  • If a trial is successful, can I keep taking the study treatment? If I was in the control group, can I start the treatment?