A new lawsuit claims Bristol-Myers Squibb Co improperly delayed the development of a drug to treat non-Hodgkin's lymphoma to avoid paying $6.4 billion to shareholders of the former Celgene Corp, which the drugmaker bought in 2019. According to a complaint filed on Thursday in federal court in Manhattan, Bristol-Myers would have owed the money had it won U.S. Food and Drug Administration approval by specified deadlines for three drugs that Celgene had been developing. The lawsuit said Bristol-Myers failed to use contractually required "diligent efforts" to win approval of the cancer drug Breyanzi by the Dec. 31, 2020, deadline, excusing it from the payments. Bristol-Myers had no immediate comment. The lawsuit was brought by UMB Bank NA, acting as a trustee for former Celgene shareholders it said lost out on the payments. Bristol-Myers bought Celgene in November 2019, and has valued the transaction at $80.3 billion. —Reuters Staff Source