The 20-year-old forward previously had spells in the Chelsea youth set-up and with the under-19 and B teams at French side Guingamp.
Dider Drogba also played for Guingamp before joining Marseille in 2003.
He joined Chelsea a year later and went on to win four Premier League titles, four FA Cups and the Champions League.
Didier Drogba, who also won a Turkish title with Galatasaray, became the Ivory Coast’s all-time top scorer before retiring in 2018.
Isaac will now be tasked with firing his new employers towards Serie C, as they currently sit seventh in Group A of Serie D, two points outside a playoff spot.
The 20-year-old mainly operates as a central striker, but can also play on the left and the right of a front three.
Prior to joining Folgore Caratese the younger Drogba had been without a club since leaving Guingamp’s B side last summer. His deal with the Italian side runs until June 30.