A group of Apple patents have been ruled invalid, casting doubt over the US trial that saw Samsung ordered to pay Apple huge damages for infringing its patents.
In August, a jury in San Jose found Samsung had improperly violated patented technology in the iPhone and iPad and awarded Apple $1.05 billion (£653 million) in damages.
According to patent consultant Florian Mueller, the US Patent and Trademark Office has now ruled that 20 patents relating to Apple's scroll technology "lack novelty".
The case involves the so called rubber-banding patents, also known as overscroll bounce, which refers to the bouncing animation that takes place when a user scrolls past the end of a page. Apple has accused Samsung of infringing these patents in its Galaxy smartphones.
The news is the latest development in the ongoing patent war between Apple and Samsung. Last week, a UK court ruled that Samsung did not copy Apple's tablet designs.