Wachtell, Lipton, Rosen & Katz and Ropes & Gray worked the largest announced mergers and acquisitions deal of the past week, as AbbVie acquired rival biotech firm ImmunoGen for $10.1 billion. Wachtell advised AbbVie, and Ropes counseled ImmunoGen.

Meanwhile, Kirkland & Ellis advised on two of the remaining four announced M&A deals in the last week of more than $1 billion.