CBS Corp. recently talked to Lions Gate Entertainment Corp. about buying the studio’s Starz cable network, according to people familiar with the matter, a deal that might complement a potential acquisition of Viacom Inc. The discussions didn’t include a formal proposal, according to the people, who asked not to be identified because the exchange was private. The talks were previously reported by the Information, which said that CBS was willing to pay $5 billion for Starz, but Lions Gate rebuffed the idea. The news sent Lions Gate soaring as much as 18% on Friday. Starz has become a key asset for the struggling Lions Gate studio, known for the “John Wick” and “Hunger Games” movies, and the company has been seeking ways to expand the network’s footprint. Lions Gate has held talks with potential partners about funding Starz’s international growth, Bloomberg reported last week. Shares of Lions Gate jumped as high as $16, marking their biggest intraday rally in 18 years. The stock had been down 16% this year through Thursday’s close. Viacom declined 1.1% in the wake of the news, while shares of CBS were little changed.