Last updated:

Updated by: Jan Barfoot

A clinical trial is a research study in human volunteers to answer specific health questions.

Clinical trials are carried out in four phases:

  • Phase I and Phase II trials check on safety – they make sure the treatment does no harm to patients. 
  • Phase III or IV trials focus on assessing how effective the treatment is, and developing it into a therapy that can be made widely available.

For more detailed information about the clinical trials process, visit these websites, or read our graphic short story, Hope Beyond Hype.

In the first instance, we recommend that you discuss your plans and options with a range of people, for example, your doctor or physician, your broader healthcare team, your family, caregivers or a support or advocacy charity related to your condition.

Consider your options carefully, participating in a clinical trial is not the best option for everyone. The closerlookatstemcells.org website has information to help people make a decision regarding a stem cell clinical trial. To search for ongoing clinical trials - in stem cell research as well as other research areas - you can also try searching one of the clinical trials databases: the EU Clinical Trials Register, NIH's ClinicalTrials.gov, the World Health Organization's International Clinical Trials Registry Platform or Current Controlled Trials. Note that not all trials are listed in these databases.

ClinicalTrials.gov disclaimer - IMPORTANT: Information on ClinicalTrials.gov is provided by the sponsor or principal investigator of the clinical study, and posting to this site does not necessarily reflect endorsement by NIH. ClinicalTrials.gov does not independently verify the scientific validity or relevance of the submitted information beyond a limited quality control review for apparent errors, deficiencies, or inconsistencies. Talk with a trusted healthcare professional before choosing to participate in a clinical study.

Some patient organizations also offer a platform for searching for clinical trials.

For more information about the clinical trials process, see:

In the first instance, we recommend that you discuss your plans with a range of people, for example, your doctor or physician, your family, caregivers and a support or advocacy charity related to your condition.

The ISSCR's website A closer look at stem cell treatments provides patient-focused information that can help you evaluate potential treatments.

Information and resources provided on the site include:

Further information is also available in the booklet What you need to know about stem cell therapies - a handbook for patients published in 2014 by the University of Alberta, Albany Medical College and the Canadian Stem Cell Network.

Sometimes it is not possible to access a clinical trial. However there are still options to get involved in research through contributing to a patient registry.

A patient or disease registry collects information about patients who are affected by a particular condition. Usually it is an electronic database. Information collected in patient registries can be used by doctors and researchers to improve medical care for people affected by those conditions.

If a disease is rare, a patient registry can allow doctors and consultants to see data from a lot of patients, rather than just the small number they see personally.

Sometimes in clinical trials a treatment is tested against the data collected from a registry, rather than have a group of patients affected by a condition get the trial treatment and a group that don't. Registries are proving to be useful for accelerating the research into orphan drugs (drugs developed to treat rare conditions or diseases) in specific populations. 

Some researchers use registries to look for eligible clinical trial subjects. If you are considering a clinical trial, participating in a registry could help put you in contact with a clinical researcher. 

For more information about patient registries and how they are used, TREAT-NMD has good further information and FAQ.

There are several listings of patient registries in Europe, including:

Please contact us if you discover others that should be on this list.

This article was compiled by EuroStemCell and reviewed by Phil Rossall, Research Manager (Knowledge Management) Age UK and Fellow, University of Edinburgh (Knowledge Exchange).