An analysis of gene therapy, a new hope and revolution for incurable cancers

In biology, the word gene can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. Gene therapy is a medical field which focuses on the genetic modification of cells to produce a therapeutic effect or the treatment of disease by repairing or reconstructing defective genetic material. The first attempt at modifying human DNA was performed in ۱۹۸۰, by Martin Cline, but the first successful nuclear gene transfer in humans, approved by the National Institutes of Health, was performed in May ۱۹۸۹. The first therapeutic use of gene transfer as well as the first direct insertion of human DNA into the nuclear genome was performed by French Anderson in a trial starting in September ۱۹۹۰. It is thought to be able to cure many genetic disorders or treat them over time.In ۱۹۸۹, the concept of human gene therapies has emerged with the first approved human gene therapy trial of Rosenberg et al. Gene therapies are considered as promising therapies applicable to a broad range of diseases. The objective of this study was to review the descriptive data on gene therapy clinical trials conducted worldwide between ۱۹۸۹ and ۲۰۱۵, and to discuss potential success rates of these trials over time and anticipated market launch in the upcoming years. A publicly available database, ‘Gene Therapy Clinical Trials Worldwide’, was used to extract descriptive data on gene therapy clinical trials: (۱) number of trials per year between ۱۹۸۹ and ۲۰۱۵; (۲) countries; (۳) diseases targeted by gene therapies; (۴) vectors used for gene delivery; (۵) trials status; (۶) phases of development. Between ۱۹۸۹ and ۲۰۱۵, ۲,۳۳۵ gene therapy clinical trials have been completed, were ongoing or approved (but not started) worldwide. The number of clinical trials did not increase steadily over time; it reached its highest peak in ۲۰۱۵ (۱۶۳ trials). Almost ۹۵% of the trials were in early phases of development and ۷۲% were ongoing. The United States undertook ۶۷% of gene therapy clinical trials. The majority of gene therapies clinical trials identified targeted cancer diseases. The first gene therapy was approved in the European Union in ۲۰۱۲, after two decades of dashed expectations. This approval boosted the investment in developing gene therapies. Regulators are creating a specific path for rapid access of those new therapies, providing hope for manufacturers, healthcare professionals, and patients.

Keywords:

Gene therapy , clinical trials , market access.