It don't know why you'd have an opening parenthesis within a field code but the closing one outside it. That said, you might try:
Code:
Sub MarkParenthesizedItalicsNoProofing()
With ActiveDocument.Range
With .Find
.ClearFormatting
.Text = "\([A-Z][a-z.][!\(]@\)"
.Replacement.Text = ""
.Forward = True
.Format = False
.MatchWildcards = True
.Wrap = wdFindStop
.Execute
End With
Do While .Find.Found
.Start = .Start + 1
.End = .End - 1
If Len(.Text) = 0 Then
.End = .End + 1
Else
If .Font.Italic = True Then .NoProofing = True
End If
.Collapse wdCollapseEnd
.Find.Execute
Loop
End With
End Sub