The 22-year-old joined the Giallorossi on a one-year loan deal worth 11.5m euros in the summer of 2012 and they have now opted to exercise their option to acquire 100 per cent of his economic rights for an additional 4.5m euros.
Destro initially struggled to live up to the high expectations following his move to Roma, but ended the 2012-13 campaign with 11 goals in 26 appearances in all competitions.
The attacker, who has already been capped at senior level for Italy, is a product of the Inter youth academy but never made it into the first team at the Nerazzurri.
He was part of the Italy Under-21 team that made it to the final at this summer's European Championship, where it was beaten 4-2 by Spain.
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