Elan has launched legal action to prevent the “irreparable injury” that would be caused by the collapse of its partnership with Biogen Idec over its pivotal multiple sclerosis drug.

The Ireland-based pharmaceuticals company is challenging a claim from Biogen Idec, based in Boston, that Elan’s recent $1.5bn (£893m) deal with Johnson & Johnson placed it in “material breach” of their profit-sharing agreement for Tysabri.