The most important resource on stem cell clinical trials is registry ClinicalTrials.gov. This registry provides the public with easy access to information on publicly and privately supported clinical studies. The ClinicalTrials.gov web site is maintained by the National Library of Medicine at the National Institutes of Health. Information (NIH) and is provided and updated by the sponsor or principal investigator of the clinical study.
Clinical Trials resources
ClinicalTrials.gov was created as a result of the Food and Drug Administration Modernization Act of 1997 (FDAMA). The site became available to the public in February 2000.
This led to the development of the ClinicalTrials.gov results database, which contains study outcomes.
Another resource, World Health Organization International (WHO) Clinical Trial Registry Platform, contains some additional information not available in the ClinicalTrials.gov registry. However, the difference is relatively small and this registry is easier to work with.
When all stem cell trials are placed on a map, we can see that vast majority of them take place in the U.S., followed by Europe.
Of the 5,101 studies, which were available on the database on August 8, 2015, 1,700 were recruiting patients and 1,769 were completed.
Clinical trials: research in human subjects
The only product that comes up as an approved treatment is Mozobil, a hematopoietic stem cell mobilizer, used in combination with granulocyte-colony stimulating factor, for the treatment of non-Hodgkin lymphoma and multiple myeloma. There are several others, such as Hemacord and Osiris, and Holoclar in Europe. This does not change the fact that approved stem cell treatments are few and far between and that is always worth checking with the relevant local regulator whether the product or treatment intervention is approved in the area or not.
Clinical research in human subjects is conducted in five phases – 0, I, II, III and IV.
• Phase 0 is an exploratory study involving very limited human exposure to the product, with no therapeutic or diagnostic goals.
• Phase 1 studies are usually conducted with healthy volunteers and emphasize safety. The goal is to find out the product’s most frequent and serious adverse events, and explore its biological effects in humans.
• Phase 2 studies gather preliminary data on effectiveness. Safety continues to be evaluated.
• Phase 3 studies gather more information about safety and effectiveness by studying different
populations and different dosages and methods of administration and by using the product in
combination with other drugs or biologics.
• Phase 4 studies occur after the approval of the product for marketing. These studies gather
additional information about a drug’s safety, efficacy, or optimal use. Not all phase 4 trials that
come up are stem cell interventions. Many of them study the effect of approved drugs and
biologics on people who received stem cell therapies.
The vast majority of these studies are in the early stages of development, and there are a considerable group of trials where the phase is not stated.
Clinical Trials: Interventional studies
The majority of stem cell research also consists of interventional studies. This means that human volunteers are assigned to interventions (for example, a medical product or procedure) based on a protocol, and are then evaluated for effects on biomedical or health outcomes.
ClinicalTrials.gov also includes records describing observational studies and programs providing access to 
investigational drugs and biologics outside of clinical trials through so called expanded access.
Analysis of sources of funding for stem cell trials shows only a small fraction of stem cell studies funded by the industry. A significant number of trials get funding from the National Institute of Health. All remaining trials get funding from entities categorized as “other,” meaning individuals, universities, and community-based organizations.
The sponsor of a clinical study is the organization or person who oversees the clinical study and is responsible for analyzing the study data. The funder is the organization that provides funding or support for the clinical study. Support may include providing facilities, expertise, or financial resources. Organizations listed as sponsors and collaborators for a study are considered the funders of the study.
There are four types of clinical study funders:
- National Institutes of Health
- Other U.S. Federal agency (for example, the Food and Drug Administration, Centers for Disease Control and Prevention, U.S. Department of Veterans Affairs)
- Industry (pharmaceutical and device companies)
- All others (including individuals, universities, and community-based organizations)
Although the number of studies conducted for a specific condition or disease does not tell us whether the study was successful or not, it does mean that the project was reviewed and approved as viable and that it received funding. The more studies available for a particular disease, the more accumulated knowledge exists, and the more likely it is that continuing research will yield convincing and consistent findings. On the other hand, isolated studies without posted results should be interpreted with caution.
