KISS. You want to find all sequences of one or more digits (to delete them). So the pattern is "\d+". Trying to specify what you don't want to find/delete is errorprone/clumsy/not necessary.
>> Set re = New RegExp
>> re.Pattern = "\d+"
>> re.Global = True
>> WScript.Echo re.Replace("a1b234c", "")
>>
abc
>>