Alnylam filed suit against Silence Therapeutics, seeking a declaration that its Patisiran RNA interference product does not infringe five Silence patents. Patisiran is awaiting approval from the FDA for treatment of hereditary transthyretin-mediated ATTR amyloidosis, a genetic disease in which misformed proteins accumulate as deposits in the heart, erves, GI tract, and other organs, bringing forth a number of different symptoms. Currently, other than liver transplants for early-stage sufferers, there are no FDA-approved treatments for the disease. Alnylam asserts that it has spent hundreds of millions of dollars in developing Patisiran. Alnylam alleges that Silence, which has no products on the market or in advanced clinical trials, has claimed that Alnylam infringes the patents by correspondence in the United States as well as by filing infringement suits in Europe and challenging Alnylam patents on the technology in Europe. These disputes are on-going. Alnylam seeks declarations of non-infringment and injunctions prohibiting Silence from asserting infringement of the patents.