Amgen’s plans to acquire Horizon Therapeutics for $27.8 billion, announced Monday, came after a slow past week in global M&A, but some dealmakers expect activity to pick up next year.

Sullivan & Cromwell and Dublin firm William Fry are advising Amgen in the year’s largest health care merger, while Cooley and Dublin firm Matheson are guiding Horizon Therapeutics. Another megadeal, the $5.2 billion deal that NRG Energy agreed to in purchasing Vivant Smart Home, was the only other billion-dollar deal in the last week, according to Law.com Radar.