So looking at the wiki page image of Remdesivir [1] I can see that this looks a lot like the sugar-phosphate backbone that is integral to DNA and RNA. If you imagine DNA as a curling ladder, the nucleoside (adenosine) is the steps, and the sugar-phosphate pairs make up the rails on either side of the steps.

The adenosine bit is attached to a five carbon sugar (pentagon with O at top) which is identical to the sugar it would be attached to in RNA. The next thing along is a phosphate with some oxygens double bonded to it, which is part of the "backbone" of DNA. The stuff attached to that phosphate is nothing like DNA or RNA.

Hope this makes sense and provides a little insight for you :)

1. https://en.wikipedia.org/wiki/Remdesivir