Intellia Therapeutics (NTLA -2.84%) and CRISPR Therapeutics (CRSP -5.54%) are pioneers in developing CRISPR gene-editing therapies. In this Motley Fool Live video recorded on Nov. 10, 2021, Motley Fool contributors Keith Speights and Brian Orelli address a viewer's question about a potentially major safety risk that both of these companies face.

Keith Speights: The next question, Brian, Mark asked a question concerning potential technical risks posed by double-stranded breaks made in DNA specifically as related to Intellia Therapeutics, also is CRISPR Therapeutics at risk? What's your take on this?

Brian Orelli: I guess this is a question about whether CRISPR, the technique, makes a break at the site of where it's supposed to, based on the sequence that you put into the CRISPR. Then it makes a break and then it gets put back together and that creates a mutation.

Usually, CRISPR is most useful for knocking out a gene. If you make a mutation and then now the gene longer works. Like for instance, there are CRISPR Therapeutics drug for beta-thalassemia and sickle cell disease, knocks out the gene that represses fetal hemoglobin. By knocking that out, then you express fetal hemoglobin and then that helps the patients since they are lacking adult hemoglobin.

The issue, I think, is probably not necessarily at that site, but it can also potentially make mutations at other sites. I think that's a risk of CRISPR, and they have to go through and make sure that the number of additional mutations that they're making is minimal.

The gene therapy companies have the same issues on the DNA that you put in for gene therapy to express a protein, can potentially integrate into some places. That can cause potential to cause cancers and stuff like that. I think it's definitely a risk, and the fact that we've only had a few patients, probably makes it harder.

Keith Speights: Yeah. To my knowledge, Brian, so far, neither Intellia nor CRISPR Therapeutics have reported significant issues with this. I'm not aware of any anyway.

Brian Orelli: Right, but they've only added a few patients, too, so we don't know.

Keith Speights: Right, it's still early.

Brian Orelli: I think it's a little hard to know exactly what the rate might be until you get into the hundreds of patients or even more if it's a low likelihood.