According to the statement on Elan's website, the company’s patents “are acknowledged as valid and enforceable under the agreement.” The patents cover transgenic mice that express human amyloid-β precursor protein (AβPP) harboring mutations that cause early-onset, familial AD. The mutations in question—an asparagine for lysine at amino acid 670, and leucine for methionine at 671—were first found in an extended Swedish family. The so-called Tg2576 mouse, developed by Karen Ashe (formerly Karen Hsiao) at the University of Minnesota, in collaboration with colleagues at the Johns Hopkins University, the University of California, San Francisco, and the McLaughlin Research Institute, expresses human AβPP harboring these mutations. In December 1996, the University of Minnesota licensed Tg2576 mice to the Mayo Medical Foundation. Mayo subsequently made arrangements with Taconic, a commercial mouse breeder, to sell and distribute the mice to investigators in non-profit and for-profit research institutions. These Tg2576 mice now appear to be covered by the Elan patents.

The Tg2576 mouse is one of the most widely used transgenic models for AD, and since the dispute erupted, scientists, in both public and private labs, who have used these animals to research AD have been standing on very shaky soil. “Many researchers have felt encumbered by the protracted legal battle and uncertainties over potential future litigation, so the settlement should certainly be viewed as a positive development,” suggested Ashe.

Exactly how the agreement will affect the cost and distribution of the mice is as yet unclear, but watch this space.—Tom Fagan.