Period of time before non-disclosure agreement programme (6)
I believe the answer is:
agenda
'programme' is the definition.
(agenda is a kind of programme)
'period of time before non-disclosure agreement' is the wordplay.
'period of time' becomes 'age' (age is a kind of period of time).
'before' is a charade indicator (letters next to each other).
'non-disclosure agreement' becomes 'NDA' (legal abbreviation).
'age'+'nda'='AGENDA'
(Other definitions for agenda that I've seen before include "Topics for a meeting" , "List of items for discussion by committee" , "Timetable" , "matters for discussion" , "Something perhaps hidden" .)