NEW YORK (Reuters) - A Manhattan federal judge dismissed part of a lawsuit by Lions Gate Entertainment Corp <LGF.N> against Carl Icahn that accused the activist investor of plotting to merge the studio with Metro-Goldwyn-Mayer.

U.S. District Judge Harold Baer rejected on Wednesday claims that Icahn failed to disclose plans about a possible Lions Gate-MGM merger, in violation of securities law. The suit also said Icahn failed to disclose an agreement to buy the 5.4 percent share in Lions Gate owned by financier Mark Cuban, who owns the Dallas Mavericks basketball team.

The judge said Icahn met disclosure requirements with amended securities filings.

Representatives for Lions Gate and Icahn were not immediately available for comment.

The lawsuit filed in October last year accused Icahn of misleading shareholders by characterizing Lions Gate's pursuit of MGM as a "misguided strategy" that would end in "oblivion" and "bankruptcy."

Lions Gate contended that Icahn was secretly plotting to merge the two studios, but only after he acquired a large position in both companies at depressed prices.

MGM filed for bankruptcy protection in November after striking an agreement with Icahn to win his support for a restructuring.

Icahn, who for years had criticized management, had launched a hostile takeover bid for Lions Gate, which produces the hit television program "Mad Men."

The case is Lions Gate Entertainment Corp v. Icahn et al, U.S. District Court, Southern District of New York, No. 10-08169.

(Reporting by Dena Aubin; editing by Andre Grenon)