Table 3 Comparison of different treatment modules
From: Gene therapy for ultrarare diseases: a geneticist’s perspective
Treatment module | Advantage | Drawback | Making a new drug for ultrarare disease |
|---|---|---|---|
Small molecule | Simple oral medication | High cost and slow in developing a new small molecular drug | Difficult |
Enzyme replacement therapy | Highly effective | High cost in development and poor brain penetration | Difficult |
Lentivirus-hematopoietic stem cell transplantation | Highly effective for hematopoietic disease, produces secretary proteins | Transplantation required, risk of lentiviral integration | Yes, could be applied to multiple ultrarare diseases |
Systemic AAV targeting the liver | Highly effective for liver disease, produces secretary proteins | Loss of effect after cell turn over, risk of AAV integration (rare) | Yes, could be applied to multiple ultrarare diseases |
Systemic AAV targeting organs other than the liver | Easy intravenous infusion, effective for multiple diseases | High cost of large quantity AAV production, AAV systemic complication, AAV integration | Difficult |
local delivery of AAV vectors to the CSF and brain | Convenient for neurological disease, persistent effect | Effectiveness depending on viral distribution in the brain | Yes, could be applied to multiple ultrarare diseases |
RNA therapy | Easy to design and produce | Need a suitable mechanism such as gene suppression or splicing | Yes, but need continuous drug administration |
Gene editing | Regulates gene expression or correct gene defect | Risk of genotoxicity | Maybe, but not applicable at the present time |