Genome editing allows scientists to add, remove or alter selected DNA sequences at particular locations in the genome. When the Nobel Prize-winning CRISPR approach to genome editing first came on the scene in 2012, it was revolutionary: researchers were very excited by the potential CRISPR/Cas offered for editing out defects in our genetic code and treating genetic diseases. Several research groups are currently exploring its clinical applications in humans and recently the US Food and Drug Administration has approved a clinical trial that will use CRISPR/Cas9 to edit genes responsible for sickle cell disease (see BioNews 1090).
'CRISPR Stops Rare Genetic Disease in New Human Trial' is one of a series of podcasts released by science news website Science Friday and hosted by Ira Flatow, which looks at the therapeutic use of genome editing in clinical trials. The episode features Professor Fyodor Urnov, from the department of molecular and cell biology at the University of California at Berkeley and director of the Innovative Genomics Institute (IGI).
Professor Urnov begins by illustrating how CRISPR-based genome editing works and describing how - by using this approach - scientists were able to stop amyloidosis, a rare and fatal genetic condition caused by the build-up of a misshapen protein – called amyloid – in organs and tissues. I particularly liked that he used the mRNA SARS-CoV-2 vaccines mechanism, which we are all now well-acquainted with, to explain the CRISPR approach, making the science behind it more relatable and easier to understand.
Flatow introduces the sickle cell study that triggered the episode and brings the audience's attention to one of the core themes of the podcast: that although very promising, the translation of genome-editing approaches into clinical practice has so far been applied to a very small cohort of patients, and thus it is very slow in delivering results.
However, do not despair as Professor Urnov outlines that combined efforts from multiple institutes and biotech companies are forecasted to produce multiple approved genomic therapies in the next three to five years. All of this is really exciting and Professor Urnov's enthusiasm throughout his account is infectious. However, the 'assuming things go to plan' sentence frequently interwoven within his account makes one begin to wonder whether any of these plans is realistic and viable, leaving the audience with a slightly bitter taste in their mouth.
Interestingly, the podcast then takes a slight detour from the biomedical discussion to an equally important one, when discussing public health: health justice. In a country like the USA, where healthcare is privatised and there is an overwhelming socioeconomic gap within the population, it's unimaginable that everyone will be able to afford genome editing therapies costing millions of dollars. While Professor Urnov's desire for a health-just distribution of these treatments is very noble and well-appreciated, it would have been more insightful to also hear his view on how to tackle health care injustice more concretely.
Flatow then asks about the future directions for genome-editing therapies While blood, neurodegenerative and cardiovascular disorders seem to be the most attractive targets, Professor Urnov stresses the need to focus on the 'rare genetic' diseases, each of which affects very few individuals but that together add up to a significant disease burden. Unfortunately, for biotech companies designing drugs for low numbers of patients is not profitable, so rare diseases are generally downgraded as 'less important'. Although no clear solution is proposed to overcome this dilemma, it is reassuring that there is rising awareness on the topic and that multiple organisations appear to be combining their efforts to fill this gap.
Professor Urnov concludes the discussion by highlighting a thrilling project carried out by a biotech company, called Verve, which deploys a next-generation form of CRISPR, called base editing, to genetically protect vulnerable individuals from heart conditions. This is achieved by targeting the genes protecting from heart attacks rather than those causing it. With this exciting news, the list of conditions that can be targeted using genome editing grows, as well as the techniques to deliver therapuetic components to various parts of the body, making us all confident that we are going to see much broader application of genome editing in the future.
Overall, the podcast is fairly informative on the science behind genome editing and its current clinical applications, although at times it feels a little cautious and vague about trials timelines. Along the way, several interesting topics come to light: I particularly liked that Professor Urnov brought up the topic of health distribution injustice, which I find crucial in this context and that as scientists we should all be thinking about; we can indeed develop ground-breaking techniques and find cures to devastating diseases, but if only a small share of the population can benefit from it, is the effort really worth it?
All this being said, the scientific progress made in the last ten years is astonishing and I'm sure we all look forward to hearing more about this fascinating piece of science and about how it can improve our lives. So, sit tight and relax because – using Professor Urnov's words – 'the next five years will be quite a ride'.