Several large U.S.-based law firms are advising on a $16.5 billion pharmaceuticals deal that will see the holding company of Novo Nordisk, the maker of popular anti-obesity drug Wegovy, acquire American pharmaceutical manufacturer Catalent.

Three firms, among the top twenty firms ranked by revenue in the Global 200, are behind the deal: Goodwin Procter for Denmark-based Novo Holdings; Skadden, Arps, Slate, Meagher & Flom for New Jersey-based Catalent and Jones Day for Catalent’s board of directors, according to the firms. Davis Polk & Wardwell is advising Novo Nordisk on a subsequent deal to ramp up its manufacturing capabilities.