Unfortunately, under the USGA rules, you are not allowed to move an out of bounds stake if it interferes with your play. The out of bounds stakes are fixed and are used to mark the boundaries of the golf course. The stakes are determined by the inside points, at ground level, of the stake. As a result, they are out of bounds and cannot be removed.
You can either play the ball as it lies, or take an unplayable drop, but removing the stake as you could for a hazard or yardage stake is not an option.