New gene therapy and gene editing therapeutics are being developed at a rapid pace and could benefit many patients with different rare genetic diseases. However, there are still some barriers to the expansion of these technologies.

The future capabilities of gene therapy and gene editing were the focus of a discussion between representatives from the National Organization for Rare Disorders (NORD), Intellia Therapeutics, and the US Food and Drug Administration (FDA). It was presented on the second day of NORD’s Breakthrough Summit that took place virtually on October 18 and 19, 2021.

Panelists addressed what gene therapy and gene editing mean for rare diseases and some of the basic differences between gene therapy (also now referred to as gene augmentation therapy) and gene editing. They also discussed how the FDA categorizes these products, and their potential to improve the lives of people with rare disorders.

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Gene Therapy vs Gene Editing

Michael Maitland, MD, PhD, is a senior director at Intellia Therapeutics, a company developing CRISPR/Cas9-based gene-editing therapeutics to treat human disease. He gave an overview of the difference between gene augmentation therapy and gene editing. 

“Gene augmentation . . . entails introducing DNA sequences into the target cells,” Dr. Maitland said. “In the case of gene editing therapy, the equipment necessary to make a direct alteration of the individual’s own DNA is the treatment of choice.”

Dr. Maitland also talked about the difference between in vivo and in vitro gene augmentation therapy. A gene is directly introduced inside the body using modified viruses, the cells are removed from the body and modified in the laboratory, and then they are reintroduced into the body.

The FDA’s Perspective

The FDA’s perspective on gene therapy and gene editing was discussed by Larissa Lapteva, MD, MHS, MBA. She is the associate director in the division of clinical evaluation, pharmacology, and toxicology of the agency.

Dr. Lapteva presented the diverse products that are regulated by the FDA’s Office of Tissues and Advanced Therapies. These include not only gene therapy products but also stem cells and stem-cell-derived products, products for xenotransplantation, functionally mature differentiated cells, therapeutic vaccines, blood- and plasma-derived products, and tissue-based products. 

Dr. Lapteva also talked about trends in related investigational new drug applications to the FDA between 2002 and 2020.

“You can see that the field was not really moving much until about 2013,” she said. She added that in the past 5 years, the agency observed a rapid increase in clinical research with these products. A substantial chunk of gene therapy investigational new drug applications is for rare genetic diseases and rare cancers.

The Patient Perspective

The panel discussion also included the input of a patient with a rare disease, Ashanthi De Silva, who was diagnosed with severe combined immunodeficiency as a baby and was the first person to receive gene therapy in a clinical trial. De Silva is a professional patient advocate and member manager at NORD. She underscored the importance of the honest relationship between researchers and patients taking part in clinical trials as well as the importance of ensuring new gene therapies are globally accessible.


Gene therapy and gene editing: current status and potential impact on the rare disease community. Presented at: NORD Breakthrough Summit 2021: October 19, 2021; Virtual.