Caution at the outset: Work on a copy of the file and be sure about the line breaks (some files have a carriage return and line feed):
You could search this site and read up on JREPL.BAT by dbenham or you could try out this hack on a copy of the file assuming:
a) Your .ICS file is a text file;
b) You only need to do this infrequently;
c) The DESCRIPTION never wraps onto the next line;
In Microsoft Word: highlight all the text (Ctrl+A) then open the find and replace dialogue using Ctrl+H on the keyboard:
Step_1 To find line breaks, type in the find box: "^l " (include the space after the lowercase L)
Step_2 In the replace box, type nothing.
Step_3 Click on replace all.
Step_4 Ctrl+click to the left of each placeholder line that you wish to remove, then press delete. (You could use the macro facility to do this automatically if this whole procedure works for you in general.)
OR you can use your usual tools to delete the placeholders.
Step_5 Save as a .txt file then rename it to .ICS