Elite independent law firms Wachtell Lipton Rosen & Katz and Cravath Swaine & Moore have teamed up with their U.K. alliance firms Macfarlanes and Slaughter and May to advise on a multi-billion-dollar pharmaceuticals deal.

Wachtell and Macfarlanes are advising Jazz Pharmaceuticals, a biopharmaceutical company based in Ireland, on its acquisition of U.K. rival GW Pharmaceuticals for $7.2 billion. Both companies are listed on the Nasdaq.