Heads of state enterprises all but suppress later event (6)
I believe the answer is:
sequel
'event' is the definition.
(sequel is a kind of event)
'heads of state enterprises all but suppress later' is the wordplay.
'heads of' indicates taking the first letters.
'all but' means to remove the last letter ('all but' can mean 'almost' or 'nearly').
'suppress' becomes 'quell' (quell can mean to suppress or quash).
'later' is a charade indicator (letters next to each other).
The first letters of 'state enterprises' is 'se'.
'quell' with its last letter taken off is 'quel'.
'se'+'quel'='SEQUEL'
(Other definitions for sequel that I've seen before include "Consequence" , "Follow-up work" , "Novel or film that completes story of an earlier one" , "Continuation of an earlier story" , "Something following a related event" .)