Allen & Overy (A&O) and Travers Smith are acting alongside two US firms on a £3.3bn deal that will see US medical device manufacturer Boston Scientific acquire FTSE 250 healthcare product company BTG.

BTG develops products used in procedures that target cancer and vascular diseases, as well as acute-care pharmaceuticals. Boston Scientific, which produces medical devices such as pacemakers and neurological surgery products, has set its sights on the UK company's therapies portfolio.

Boston is being advised by Shearman & Sterling, Travers and Arnold & Porter, while A&O is sole adviser to BTG, fielding a team led by co-head of corporate Richard Browne, supported by M&A partner Matthew Appleton, competition partner Alasdair Balfour and employment partner Paul McCarthy, with New York-based antitrust head Elaine Johnston dealing with the competition law issues.

Shearman took the lead role for Boston, while Travers handled share scheme aspects of the deal, deploying head of incentives and remuneration Mahesh Varia.

Shearman's team is being led by London finance partner Ian Goalen, New York M&A partner Clare O'Brien and London partner Laurence Levy, who heads up the US firm's Europe and Middle East M&A practice.

The deal, which has now been approved by the boards of directors of Boston Scientific and BTG, is expected to close in the first half of 2019, subject to regulatory and shareholder approvals.

Boston Scientific's legal team is led by general counsel Desiree Ralls-Morrison, who joined from Boehringer Ingelheim last year.