Professor Peter Robbins Podcast Transcript
A summary of the key aims and objectives of the study entitled "Almitrine bismesylate in COVID-19"
What happens with patients with more severe COVID-19 disease is that they develop parts of the lung which become particularly diseased, and lots and lots of blood is going through those parts of the lung, and that blood doesn’t pick up oxygen properly, which means when the blood leaves the lung, the oxygen level in the blood is just too low. Now, you can increase the amount of oxygen that people breathe, and that helps by a considerable degree, but of course if the oxygen that you breathe in, if the blood going through the lungs never gets near the gas, then it can’t actually help. So we have this problem of what’s called a shunt blood flow going through the lungs, which isn’t getting close to any gas, and that’s keeping the oxygen low in the blood leaving the lungs, even when people are breathing really quite high oxygen mixtures.
What we hope almitrine is going to do is constrict the blood vessels that actually go to the diseased parts of the lungs and narrow those down, and in that way re-route the blood from the most diseased parts of the lungs towards those parts where there’s less disease, and where the blood can pick the oxygen up. Now, the reason we think almitrine may do this is that almitrine effectively increases what’s called acute hypoxia sensing in various organs in the body, including the blood vessels of the lung, and because the oxygen’s particularly low there, we’re hoping that that’s the thing that will make the almitrine work preferentially on those blood vessels which are in the low oxygen areas. We have some real hope that it will work from almitrine’s previous use in acute respiratory distress syndrome, where there are actually a number of studies which show that if you give almitrine to people with acute respiratory distress syndrome and who have a shunt flow of blood like this going through the lung without never getting near the gas, then almitrine does indeed have that effect. So our question is: will the effect that has already been observed in acute respiratory distress syndrome carry across into COVID-19 disease and help increase the oxygen in these patients who have very low levels of oxygen in their arterial blood?
The idea of Phase A is just to give a single test dose of the almitrine and see whether we can actually increase the oxygen levels in the arterial blood of patients, see if we can actually push those oxygen levels up. If we do that, it tells us that almitrine is having a biological effect in the lung. Of course, we want that to carry over into real patient benefit. The second phase of the trial is concerned with giving almitrine over the longer period of time; giving it over 7 days. And our measure of success there will be whether we can reduce the need for other forms of respiratory support. So what we’d like to be able to do is reduce the amount of extra oxygen that we have to give patients and indeed try and see if we can avoid patients needing to go onto a ventilator and progress through more invasive forms of respiratory support. So, what we want to see is whether almitrine can really change the level of respiratory support that a patient needs.