Natalie Ratabesi has left her position as creative director of Philosophy after working with the brand since October 2012.
The news comes after a statement that the labels parent company, Aeffe, reported poor performance during the first three months of 2014.
At this time, managing director and chief financial officer Marcello Tassinari commented that the company was taking action to improve the brands development, reports WWD.
Since Alberta Ferretti founded the label in 1984, Natalie was the first designer that she granted full creative control with the aim of focusing more attention on her eponymous line.
With no successor named there will be an in-house team designing the spring/summer 2015 collection, which will show in Milan this September.