You are here releases first database of in vivo gene therapy clinical trials

Dale Stibbs, Pedro Silva Couto, and Frances Verter


Our newest database, released May 2021, holds 835 clinical trials registered worldwide 2011-2019 in which gene therapy is given in vivo without cells as carriers.  This is a very specific data product with careful screening of the clinical trials. Readers who are interested in gene therapy that is delivered by cells can find those trials inside our existing compilations of advanced cell therapy clinical trials.

Number clinical trials in vivo Gene Therapy per yearThose who work in gene therapy may be aware of other resources that provide clinical trial data for free, so we must explain how our product is different. For example, the Journal of Gene Medicine operates a searchable database of clinical trials. There are also scholarly review articles of gene therapy clinical trials, most recently covering trials through 20171.

Our gene therapy database is comparable in data quality to a scholarly publication, but it is curated through a more recent endpoint, and the list of trial descriptions can be downloaded. There are websites that automatically collect and display clinical trials from registries, and contain very recent data. But these software-driven resources are collecting trials based solely on keywords. A high percentage of their content is false positives that a human reviewer will recognize are not gene therapy trials. As a result, the statistics of how many gene therapy trials fall into various categories are not accurate when generated from databases compiled by automatic software. Our initial release of 835 trials from the years 2011-2019 is based on human screening of about 39,600 trials from all of the world’s national trial registries.

We have chosen in this data product to focus on in vivo gene therapy, where the gene modification takes place inside the patient’s body. This area of gene therapy research has struggled to achieve approved and commercially successful products2. The media has primarily covered the success of gene therapy products like CAR-T therapy, where the gene modification takes place in cells ex vivo, and then the modified cells are introduced to the patient. The other compilations of gene therapy almost invariably intermingle the in vivo and ex vivo therapies.

Our first graph shows the number of clinical trials per year performing in vivo gene therapy. The number of trials per year has roughly doubled from 2011 to 2019 (from about 60 to about 120 trials) and this growth rate is comparable to the general growth of advanced cell therapy during those years (from about 350 to about 750 trials).  Whereas, the number of CAR-immunotherapy trials increased 25 -fold over the same timeframe (from 9 in 2011 to 251 in 2019).

Sponsors of in vivo Gene Therapy clinical trials, per yearDelivery used by in vivo Gene Therapy clinical trials 2011-2019

Our second graph displays the dominant source of funding for in vivo studies of gene therapy over the years from 2011 to 2019. Whereas initially the clinical trials were split half and half in terms of academic versus industry funding, by 2019 we found that 70% of the trials were supported by corporate sponsors.

Our final graph shows the fractions of in vivo gene therapy trials that rely on viral vectors versus non-viral delivery, such as plasmid DNA and other methods. For the in vivo gene trials as a whole, the viral vector fraction is 79%.  More detailed breakdowns by virus type are available within our database.


  1. Ginn SL, Amaya AK, Alexander IE,  Edelstein M, Abedi MR. Gene therapy clinical trials worldwide to 2017: An update. Journal of Gene Medicine 2018; 20(5):e3015
  2. Keeler AM and Flotte TR. Recombinant Adeno-Associated Virus Gene Therapy in Light of Luxturna (and Zolgensma and Glybera): Where Are We, and How Did We Get Here? Annual Review of Virology 2019; 6:601-621