The U.S. Patent and Trademark Office has attached a "Notice of Abandonment" note to The Last Guardian's trademark.
Sony registered the trademark for the much-delayed title three years ago but August 6 marked its expiry date.
Under current United States trademark law, the firm had until January 2013 to "prove use in commerce" for the PlayStation 3 exclusive. However, with the game still not seeing the light of day, the status of the trademark has changed to "abandoned".
Sony later confirmed that Team ICO-developed The Last Guardian is still in development but they have "nothing new to report at this time".