Yervoy does have a REMS—from BMY’s PR (#msg-61381246):
The YERVOY Risk Evaluation and Mitigation Strategy (REMS) consists of a Communication Plan to inform potential prescribers and supportive healthcare providers about serious adverse reactions associated with YERVOY. To support this communication plan, Bristol-Myers Squibb has put in place a system that will enable the company to deliver these educational materials to the appropriate healthcare professional at the time of product order.
“The efficient-market hypothesis may be the foremost piece of B.S. ever promulgated in any area of human knowledge!”