Sub Macro1()
Dim oCC As ContentControl
Dim i As Integer
Dim strValue As String, strText As String
Dim Coll As Collection
    Set oCC = ActiveDocument.SelectContentControlsByTitle("Quality 2015").Item(1)
    Set Coll = New Collection
    With oCC.DropdownListEntries
        For i = 2 To .Count
            strText = .Item(i).Text
            strValue = onlyDigits(.Item(i).Text)
            strValue = Replace(strValue, "9001", "9001:2015 - ")
            Coll.Add Trim(strText) & "|" & strValue
        Next i

        .Clear
        .Add "Choose an item", ""
        For i = 1 To Coll.Count
            .Add Split(Coll.Item(i), "|")(0), Split(Coll.Item(i), "|")(1)
        Next i
    End With
End Sub

Private Function onlyDigits(s As String) As String
Dim retval As String
Dim i As Integer
    retval = ""
    For i = 1 To Len(s)
        If Mid(s, i, 1) >= "0" And Mid(s, i, 1) <= "9" _
           Or Mid(s, i, 1) = "." Then
            retval = retval + Mid(s, i, 1)
        End If
    Next
    onlyDigits = retval
End Function