[wiggles_md]

Restoring that requirement across the board would have a profound negative impact on the biotech (and likely I would guess, advanced materials) sectors. Think of, for example, discovering a useful small molecule, and wishing to build a moat around it while you do the med chem work for a lead compound.

[jcranmer]

You have to at least build the compound to do the assay to actually find out that it's useful.

[wiggles_md]

What you describe is the current practice. What I am trying to suggest is that it is reasonable to be able to use a Markush claim for obvious related compounds.