An endoluminal sleeve device (1) for internally lining a section of the GI tract comprises a sleeve (2) configured for deployment inside the duodenum, an anchoring portion (8) forming a proximal sleeve end (4), the anchoring portion (8) comprising shape memory material having at least two separate phases corresponding to a first shape memory state and to a second shape memory state, wherein in the first shape memory state the anchoring portion (8) is folded in a collapsed shape, in the second shape memory state, the anchoring portion (8) is unfolded in an expanded tubular shape adapted to shape interfere with a target anchoring location in the GI tract.
