Depending on the format of the VPX project - is it standard DVD or HD destined for BD disc and what you want to do in Final Cut determines the format you export the video as - FCP can be very fussy about HD file formats and cannot read VPX project files.
You will have to export the video to a suitable compressed or uncompressed format (be prepared for very large file size with uncompressed video) that FCP can read and import .