Sullivan & Cromwell and Cadwalader, Wickersham & Taft are acting as lead advisers on Valeant's $14.5bn (£9.5bn) acquisition of gastrointestinal drug specialist Salix.

Valeant will pick up all of Salix's outstanding common stock for $158 (£103) per share in a transaction that will entail the Quebec-based group taking control of Salix's portfolio of 22 products, including prescription brands Xifaxan, Uceris, and Apriso.

Valeant's chief executive Michael Pearson pointed to Salix's "promising near-term pipeline of innovative products" as a further reason to buy the company.

Sullivan's six partner team advising Valeant is spread across its Los Angeles, Palo Alto, New York and Washington D.C offices.

The firm's team includes partners Alison Ressler and Sarah Payne, who are advising on corporate issues; partner Nader Mousavi, who is advising on intellectual property; and partner Matthew Friestedt, who is advising on executive compensation and benefits.

The firm is also advising on the financing of the deal, with partners Dennis Sullivan and Neal McKnight, as well as tax aspects.

Cadwalader is advising Salix on the deal.

The all-cash offer will be financed through a combination of bank debt and bonds run by a syndicate of banks led by Deutsche Bank and HSBC.

The deal is the third major pharmaceutical industry deal so far in 2015.

Top roles on Pfizer's $17bn (£11bn) acquisition of injectable drugmaker Hospira in February went to Clifford Chance, Ropes & Gray and Skadden Arps Slate Meagher & Flom.

In January, Slaughter and May, Davis Polk & Wardwell and Skadden lined up on Shire's $5.2bn (£3.4bn) acquisition of US company NPS Pharmaceuticals.

Cadwalader took the lead role on Pfizer's $3.6bn (£2.3bn) acquisition of King Pharmaceuticals in 2010.