In early 2014, when George Cary stepped in to defend Sanofi-Aventis SA against claims that it had illegally cornered the market to provide hospitals with blood thinner, the company had already spent five years trying unsuccessfully to beat the multibillion-dollar litigation.

Less than four months later, after Cary argued for summary judgment, a federal judge in New Jersey agreed to toss the case. The Cleary Gottlieb Steen & Hamilton partner finished the job this week, convincing a federal appeals court that Japanese drugmaker Eisai Co. Ltd. didn’t back up its antitrust allegations against Sanofi.