Gene therapy is a rapidly developing field of therapeutic treatment that holds the potential to treat a wide range of diseases, including cystic fibrosis, sickle cell, cancer, heart disease, diabetes, and human immunodeficiency virus (HIV)/ acquired immunodeficiency syndrome (AIDS).
In 1988, the first clinical trial of human gene therapy was conducted for the treatment of Gaucher disease. Since then, significant strides have been made in the field of gene therapy, propelled by enhancements in analytical technology, genomics, and molecular biology. For example, the United States Food and Drug Administration (FDA) has approved 37 cell and gene therapy products which have been licensed to treat several conditions and currently, there are over 1,100 open gene therapy clinical trials and ribonucleic acid (RNA)-based therapy clinical trials globally.
This article explores how trapped ion mobility spectrometry (TIMS) is advancing research into gene therapy products and progressing the development of new treatments for diseases that were previously considered untreatable.
History of Gene Therapy
Speculation about gene therapy began in the 1960s when scientists hypothesised that introducing deoxyribonucleic acid (DNA) sequences into patients’ cells could hold the key to curing genetic disorders. Though without protection from a carrier, the nucleic acid material was rapidly eliminated from the body.
It wasn’t until the 1980s when the first notable advancements in gene therapy were made with the discovery of vectors as a delivery method and a paper was published demonstrating the use of a virus to insert genes into blood-forming stem cells in mice. Then, in 1990, came the first human success story in a
patient who was born with a severe combined immunodeficiency (SCID) due to lack of the enzyme adenosine deaminase (ADA). Doctors delivered a healthy ADA gene into the patient’s blood
cells, using a disabled virus unable to spread in the body. Despite initial setbacks, including the death of a patient in 1999, subsequent trials demonstrated promising results, heralding the potential of gene therapy for treating genetic diseases.
Having acknowledged the crucial need for a delivery system to protect the nucleic acid, usually small interfering ribonucleic acid (siRNA) and on occasion DNA, as it travels through the body to reach the target cells, researchers are now investigating a variety of delivery options, including viral vectors and non-viral vectors (such as nanoparticles and liposomes) to improve gene delivery efficiency and specificity.
The Rise of Recombinant Adeno-associated Virus (rAAV) Vector
AAV is a non-enveloped virus belonging to the genus Dependo-parvovirus in the family Parvoviridae that is non-pathogenic, replication-defective and packages a single-stranded viral DNA. As a small virus (approximately 20–25 nanometer in diameter), rAAV can carry a small payload of single-stranded DNA (ssDNA) which can be used for therapeutic purposes. The ssDNA is encapsulated in viral proteins and transported to the site of action in the body.
rAAV has emerged as a leading gene delivery vehicle (vector) for in vivo gene therapy due to several advantages, namely high infectivity, efficient delivery of therapeutic genes into target cells, and low pathogenicity, minimising the risk of causing disease in the host. AAV also possesses widespread tissue
tropism, allowing it to target a broad range of tissues throughout the body. Furthermore, rAAV-mediated gene expression demonstrates long-term persistence, even in non-dividing cells.
Recent advancements in developing clinically desirable rAAV capsids have contributed substantially to the growth of the gene therapy field. Researchers continue to refine rAAV vectors to enhance their targeting specificity and reduce unwanted immune response to further improve the efficacy of gene therapy
treatments. Developments in vector design and engineering to provide reliable and robust delivery look set to advance targeted gene delivery, while minimising adverse effects. However, final preparation, formulation, and characterisation of rAAV drug substances are fundamental to support preclinical and clinical applications.
