Introduction:
As the demand for synthetic genes keeps on increasing, CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats), a gene editing technique full of promise, is being used more and more in the food industry, agriculture and in industrial products. A market research company states that the genome editing market, including techniques such as CRISPR, transcription activator-like effector nuclease (TALEN) or Zinc finger nuclease (ZFN), is expected to increase from about $1.85 billion in 2014 to $3.51 billion in 2019, at a compound annual growth rate (CAGR) of 13.5%. But more importantly, this technique will revolutionize medicine and perhaps enable doctors to offer better healthcare to patients.
Clinical Trials: Therapeutic Uses of the CRISPR Technique.
CRISPR can be used to cleave DNA at a precise location and two repair pathways can then be used. The most active mechanism is the Non Homologous End Joining (NHEJ) method that is very efficient but error prone as small sequences can be inserted or deleted from the DNA. Alternatively, when a repair template is given then Homology-Directed Repair (HDR) occurs, i.e., an exogenous (foreign) DNA sequence can be introduced at a specific location on a genome. HDR pathway is less error-prone but also less efficient. Further research is required to make this pathway as efficient as NHEJ pathway.
As compared to ZFN or TALEN or similar gene editing techniques, CRISPR is an economical and more precise technique. Hence, scientists want to study the efficacy of gene therapies using the CRISPR technique for various disorders. At present, labs such as Dr. Zhang and Dr. Bhatia’s lab at MIT, are interested in developing gene therapies using CRISPR for viral disorders such as Hepatitis B. Scientists would need to edit genes from the stem cells and then transfer these cells into the patient’s bloodstream. Additionally, researchers see promise in curing disorders such as familial Alzheimer’s disease, HIV, Huntington’s chorea and beta-thalassemia using CRISPR. More pre-clinical research is indeed necessary before it can be used for clinical trials in humans. Recently, the Food and Drug Administration (FDA) has approved one clinical trial in humans that uses ZNF technique for treating hemophilia B patients.
Many pharmaceutical and biotech companies are looking forward to commercializing the innumerable possibilities the CRISPR technique has to offer to healthcare. Editas, Caribou Biosciences, Sangamo Biosciences, Intellia, and Cellectis are some of the leading companies that will advance gene editing technology by making it available for therapeutic purposes. New startups with new ideas are emerging at a fast pace which makes gene editing therapies a dynamic field full of promise.
Future Directions:
In spite of its unlimited potential, the scientific community appeals for its cautious use in healthcare, in particular when used on human embryos; off-target mutations resulting from gene editing and their unintended consequences are a matter of serious concern. Long term studies are essential to understand how edited genes are passed on to the future generations. However, stringent regulatory requirements and adverse public views or opinions are considered major hurdles for the growth in usage of the CRISPR technique. A careful but bold approach while using CRISPR might help us to bring a positive change in current healthcare. With rigorous scientific studies, evolving ethical guidelines, and increased awareness in the community, CRISPR will certainly revolutionize medical care.
References:
http://www.marketsandmarkets.com/PressReleases/genome-editing-engineering.asp
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4607175/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4649911/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4585242/
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