Wayne Pivac's side, fresh from sealing the Triple Crown against England, made short work of the error-plagued Azzurri and will clinch a stunning Grand Slam if they beat France in Paris next weekend.
Wales sit top of the table with 19 points, while second placed France lost 23-20 to England at Twickenham.
France and England have 10 points with the French having a game in hand against Scotland.
The French will need to win both of their remaining games to have any chance of winning the title.
Italy, who suffered their 31st consecutive Six Nations defeat, are rooted to the bottom of the table with zero points, having conceded 187 points in their four defeats so far.