Profitable, as vital cure could be (9)
I believe the answer is:
lucrative
'profitable' is the definition.
('lucrative' can be similar in meaning to 'profitable')
'vital cure could be' is the wordplay.
'could be' indicates anagramming the letters.
'vital'+'cure'='vitalcure'
'vitalcure' anagrammed gives 'LUCRATIVE'.
'as' is the link.
(Other definitions for lucrative that I've seen before include "Moneymaking" , "Well-paid" , "Producing a sizeable profit" , "Highly profitable" , "Making money" .)