On March 28 2011 Swift discovered the gamma-ray transient event SWIFT J164449.3+573451. The first and up to now only event of its kind, it has been interpreted as the result of tidal disruption of a star on a (super)massive black hole (or, alternatively, as the activity onset of a Galactic Nucleus). The source has been extensively studied acrodss the whole electromagnetic spectrum. The X-ray emission is still detected after more than one year since the beginning of the activity and it is monitored daily by Swift. Study of the long term X-ray behaviourlight curve and spectrum could further our comprehension of this puzzling event.