Bisantrene and COVID-19 Coronavirus, page-16

OK I had a chance to read the paper (pre-print) over lunch. I should preface that I am not an expert in molecular modelling and docking, but I do have some understanding of the area. If we have some real experts here I would certainly love to hear from you.

What does the paper show?
This is a computer modelling study. The author took the crystal structure (3D model) of the COVID-19 protease (this is one of the essential parts of the coronavirus, without a functional protease the virus can’t replicate) and did a docking study (I will explain what docking is below) with 3639 “approved” drug structures to see what was calculated to bind to the proteases. He found that some of the drugs appeared to bind tightly to the proteases and potentially inactivate it (i.e. kill the virus). Most of the drugs were known anti-virals for other viruses, but Bisantrene was also on the list at number 13 out of 3639.

What is Docking?
Docking is a way computational chemists can predict how a drug will behave in real life. The best analogy is with 3D CAD where a designer models the parts for a car or plane in software to work out if all the parts will fit together in real life. Docking can be an efficient way to screen many possible drugs to see if they will bind to the protein of interest. The downside with docking is that while it is quick and easy to do, it does have a high false positive and negative rate. The reason why is modelling the binding is technically very complex and the software tools used don’t give a perfect answer.

What does this mean for Bisantrene?
This is tricky to answer. The best answer is this paper suggests that it would be worth doing further research in the lab to see if Bisantrene really does bind to the COVID-19 protease and kill the virus, or if the whole thing is just a false positive. Luckily this is relatively easy and quick to do (you can do it in cell culture in the lab). It is my understanding that the CSIRO is currently running a program screening existing and new drugs to see if they can find new treatments for COVID-19. You can apparently just submit a form and they will do the assay for you for free if they think your drug has potential.

What does this mean for RAC?
This is even harder to say. If it turns out that Bisantrene does kill the virus in cell culture the next stage would be to look at what dose is needed. If it able to work at a low enough dose that didn’t cause problems for the patients, then in theory a small trial could be run on infected patients with serious illness. Since Bisantrene has been used in lots of people already it should be much faster to get this into the clinic than a drug that has never even been tested in animals.

What are we going to do?
I can’t say at this point. Certainly think some more.