Roche Holding announced Monday its $8.3 billion acquisition of InterMune, a suburban San Francisco-based company lung disease drug developer, marking the latest in a series of deals by the Swiss drug giant.

The proposed purchase of InterMune is Roche’s largest deal since its $46.8 billion takeover of Genentech in 2009, and second major deal this summer following Roche’s $1.7 billion buy of San Diego-based Seragon Pharmaceuticals in July.

Roche, which has also recently been linked as a potential buyer for the remaining stake in Japan’s Chugai Pharmaceuticals that it doesn’t already own, turned to Sidley Austin to advise on its Seragon acquisition. But the Basel-based acquirer has returned to Davis Polk & Wardwell—the Am Law 100 firm that handled the Genentech deal and Roche’s $450 million purchase of medical testing equipment maker IQuum earlier this year—for its InterMune acquisition.

Arthur Golden, a senior corporate partner at Davis Polk and former member of the firm’s management committee, is working with fellow corporate partner Marc Williams in leading a team from the firm representing Roche on its bid for InterMune. The Davis Polk duo also represented for Tyson Foods earlier this summer on its successful takeover battle for Hillshire Brands, as well as ConAgra Foods two years ago on its $6.8 billion acquisition of Ralcorp.

Golden previously led the Davis Polk team that handled Roche’s acquisition of Genentech five years ago—he told The Am Law Daily at the time that Roche had been a client for 20 years. Other lawyers from the firm working on the current deal for InterMune include antitrust partner Ronan Harty, executive compensation head Edmond FitzGerald, executive compensation partner Jean McLoughlin, tax partner Michael Mollerus and associates Lee Hochbaum, Gillian Moldowan, Brian Snyder and Zain Ur Rehman.

Gottlieb Keller, a member of Roche’s executive committee, has served as the company’s general counsel since late 2007. Roche’s deputy director of the corporate law group Beat Kraehenmann is heading up matters in-house for the drug giant on its purchase of InterMune, which has been approved by the boards of both companies.

Cravath, Swaine & Moore has taken the lead outside legal advisory role for InterMune with a team led by M&A partners Faiza Saeed and Ting Chen, tax partner Michael Schler, executive compensation partner Eric Hilfers, antitrust partner Christine Varney, IP partner David Kappos and associates Margaret D’Amico, Amanda Fenster, Nicole Foster, Jay Gill, Benjamin Landry, Julia Onorato, Jennifer Tanaka and Jennifer Uren. A merger agreement filed by InterMune with the Securities and Exchange Commission states that its sale should close by year’s end. (Both Kappos and Varney have joined Cravath’s partnership ranks from public service in recent years.)

Li-Hsien “Lily” Rin-Laures, a partner with Chicago-based IP boutique Marshall, Gerstein & Borun, is serving as IP counsel on the deal for InterMune along with the company’s director of legal affairs Carolyn Tang. InterMune’s general counsel Andrew Powell, who joined the company last year, is heading up matters in-house on the transaction.

Brisbane, Calif.-based InterMune, which went public more than a decade ago, develops drugs that treat diseases affecting immune system and pulmonary functions. The company’s most successful drug is pirfenidone—called Esbriet in Canada, Europe and Japan—which treats a fatal scarring of the lungs known as idiopathic pulmonary fibrosis. Esbriet has not yet been approved for use in the U.S., as the Food and Drug Administration sought more tests for the drug in 2010.

The sale of InterMune, which has been a potential takeover target for years, comes less than a year after the U.S. Supreme Court refused to hear the appeal of former CEO W. Scott Harkonen, sentenced to six months home confinement in 2011 for a 2009 wire fraud conviction stemming from a controversial company press release he authorized more than a decade ago. Sidley Austin has been representing Harkonen in the litigation that caused him to resign as head of the company back in 2003.

Sullivan & Cromwell corporate partners Frank Aquila, Brian Hamilton and Krishna Veeraraghava and Gibson, Dunn & Crutcher corporate partner Jonathan Layne and counsel Andrew Hirsch are currently representing InterMune’s financial advisers at Centerview Partners and Goldman Sachs, respectively, on the target’s proposed sale to Roche.