Yes you can, but you need to add a quantifier. For example:

 s/ ^ ([\w_-]+) \. ([\w:]+) [A-Z]{3} \. /$1.$2./x;
[download]

or possibly:

 s/ ^ ([\w_-]+) \. ([\w:]+) [A-Z]+ \. /$1.$2./x;
[download]

But you might have to watch out that [A-Z]+ will not match some other uppercase letter(s) before in some other file names.