(Reuters) – AbbVie said on Wednesday it would buy Cerevel Therapeutics, a developer of drugs for neurological conditions, for about $8.7 billion in a bid to replace revenue as its arthritis drug Humira faces a raft of new competition. It marks the second large deal for AbbVie in the past week, coming days after it agreed to buy cancer drug developer ImmunoGen for $10.1 billion in cash, highlighting its appetite to place big bets on promising new medicines. It is paying $45 per share in cash for Cerevel, which is developing drugs for Alzheimer’s, Parkinson’s, psychosis, epilepsy, and panic diso…