Phases of research
Phase I
Phase II
Phase III
Phase IV
Moving closer to clinical applications
Since the first human gene therapy trial in 1989 [1] over 1340 clinical trials have been completed, are ongoing or have been approved in 28 countries, using over 100 genes. Since 2004, over 400 new gene therapy clinical trials have been initiated or published [2].
Phases of research
The development of new therapies typically takes about 10 to 12 years. After thorough testing in the laboratory and animal experiments, patients and volunteers are involved as experimental subjects. From that moment the research roadmap from bench to bedside is divided into 4 phases.
Phase I
The first phase of clinical research focuses on the safety of the investigated new therapy. Dose escalation studies provide insights on adverse events.
Because this kind of studies are performed on relatively little subjects and without controles, no evidence-based claims on the effectivity of the therapy can be made. In practice, big headlines in the media are often based on this phase of clinical studies.
Phase II
The goal of this phase is to find the optimal dosis of a new therapy or drug, which has been found safe in phase I. Participants are often patients that have no prospects of recovering from conventional therapies and patients for who there is no therapy available at all.
Expectations are often high when results of phase II research ar e published, but again, the low number of participants and the lack of control subjects, make far reaching conclusions impossible.
Phase III
Phase III consists of the so called double blind placebo controlled trial. Different groups af patients are treated. Some receive the new product, others receive a placebo. In this way scientist and doctors want to find out what effect the new therapy has.
This phase of research can provide scientific proof of the effects of a new therapy, if any.
Phase IV
When a new therapy is found to be effective, some administrative procedures have to be followed. The product has to be registered, in the case of Europe, at the European Medicines Agency (EMEA), which can be a time consuming process.
When the product is licensed for therapeutical use, it can be described by doctors. National administrations have to decide in what way the therapy will be insurrenced.
Moving closer to clinical applications
The vast majority of gene therapy clinical trials performed to date are phase I or I/II. The two categories combined represent 80.9% of all gene therapy trials. 15.7% are phase II trials, and phase II/III and III trials represent only 3.4%.
There are slightly more trials in phase II, II/III and III than in 2004 (19.1% in 2007 compared to 15% in 2004) possibly indicating that gene therapy is slowly moving closer to clinical applications.
References
1. Rosenberg SA, Aebersold P, Cornetta K, et al. Gene transfer into humans – immunotherapy of patients with advancedmelanoma, using tumor-infiltrating lymphocytes modified by retroviral gene transduction. N Engl JMed 1990; 323: 570–578.
2. These data are obtained from the ‘Gene therapy clinical trial worldwide’ database, provided by the Journal of Gene medicine www.wiley.co.uk/genmed/clinical. The database was updated in July 2007. The data are compiled and regularly updated from official agency sources, published literature, conference presentations and posters and from information kindly provided by investigators or trial sponsors themselves. The database does not contain all gene therapy trials, because some national official agency sources treat their data as confidential, like Austria en Switzerland. Other countries provide information in their own language only, like China and the Netherlands. From these countries the data can be incomplete.
3. Michael L. Edelstein, Mohammad R. Abedi, Jo Wixon. Gene therapy clinical trials worldwide to 2007 - an update. Journal of Gene Medicine 2007;9(10): 833-842.
Eelco Soeteman
Last updated december 3, 2007
This information is developed by Egan by order of Consert.
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