Stuart Peltz
Analyst · Bernstein. Please go ahead
Sure. Thanks for that. And so yes, in general, our approach is really – we used in a sense of chemical genomics approach in terms of identifying molecules first in a high throughput screen and then go into to cell an animal-based molecule. And they’re always counter screened against a number of other, what we think are similar, yet not identical splicing events to watch. And so we look very carefully at that as well. Then also used in a sense, safety toxicology as an important measure as well, because at the end of the day, whether it’s on-target or off-target is what we tend to want to find that out. So this occurs quite early within our screening tier. And so we build a screening tier, both looking at – looking at in a sense, the effectiveness of the compounds for selectivity and specificity. We also do deep sequencing and RNA seek to monitor what else within the genome they may hit. So, and we continue to try to improve not only the efficacy but the selectivity collectivity of that. We find that we’re capable of doing that. And as the molecules become more effective, it tend to be in the low in the animal range. It tend to be far more selective as a consequence of that. And then obviously, we put them in through pharmaceutical – not only do the efficacy and safety, but look at the pharmaceutical co-properties that go along with that. And that’s a long laundry list of things that we look at, whether it’s induces it, whether it aimed assay issues. All the things that we look – that is known to look for that we – if we find some issue with it, we work it out and try and get that out. Until finally, we get a compound that we want to move forward on to do what we’d say is to move forward like a development compound that we then do larger GMP scaling of the product. So we have that synthesizing the GMP manner than does do GLP safety toxicology studies. What we’ve talked about in the past for a Huntington’s disease is that, this, we think that an orally bioavailable product, much like analogous to SMA, would really be the most competitive product. And so this is a very important program for us where we would anticipate as need be to continue to have as many compounds to move forward as we can. As I said in my prepared remarks, we already have a compound that we are doing GMP scaling and going to be moving into the safety toxicology, such that, as we’ve always said, we anticipate to have it in the clinic, next year. So I think that’s an exciting point here, that we’re moving forward on this compound, continue, obviously to build out the patent, IP profile around all of that. And then we’ve already shown in animal models that it reduces HTT, not only in the brain, but also in other tissues as well. And we’ll have the advantage that we’ll be able to look into blood and see a reduction of that. These compounds are highly effective. We’re shooting for probably a 60 – between 50% and 60% reduction with these molecules are effective enough to go pretty low. And so we’re capable. I think the nice thing about a small molecule also is that not only do we know it penetrates the blood-brain barrier and gets into – and obviously because of the blood exposure gets to all cell within the brain, but it also gets into blood and skin and very capable of actually monitoring with the effect of what exposure causes a reduction, and the fact that as that we could then go and figure that out to what effect reduction you’ve seen brain. So we have a very good ways of titrating what the appropriate – what the appropriate exposure is to get a 50%, 60% reduction. And that’s the way of that we’re – that’s the way we pick the compounds and begin to define what would be the appropriate dose of that. And then we can go into humans. And really as a consequence of being able to measure it in the blood, we’re able to say, what reduction we’re able to see. And I think one thing that we probably didn’t push hard enough in the SMA program is that very early on in healthy volunteers, we were able to show that there was a reduction of SMA. Analogous to that, we’re going to be able to show that the molecule we chose, we’ll be able to say, with the hypothesis, do you reduce HTT and can you observe that in the blood? And we did that in SMA and that gives us a lot of confidence to be able to move forward because of what you see in the blood is what we saw in the brain. So that’s in a sense, one of the first, even in healthy volunteers, I think we’re going to have a good idea whether we hit the target we want, effect this splice, reduce the splice and then move on. And then in terms of the product profile, I think we’ll be sort of talking about that in more detail over the next call.