Kirkland & Ellis' M&A conflicts crisis deepened on Tuesday, when a federal magistrate judge in Pittsburgh recommended that the firm be barred from advising Israel's Teva Pharmaceutical Industries Ltd in its $40 billion hostile bid for Mylan NV.

But Kirkland's loss is Sullivan & Cromwell's gain, as Teva announced that S&C will step in to advise the company in the cross-border takeover fight.

It's too early to declare the litigation for Mylan, since Tuesday's report by U.S. Magistrate Judge Lisa Pupo Lenihan could be rejected by the district judge. Lenihan blasted Kirkland for ignoring conflicts related to its past work for Mylan, finding that the firm breached its ethical duties. Kirkland immediately vowed to contest Lenihan's findings, saying in a statement that it rejected Mylan's conflict of interest claims.