IL2 has a 6% response rate, IPI/Yervoy has 20-30% percent and is far less toxic. Some do believe there is a synergy between the two drugs, but I don’t believe one has to preceed the other. Also, that synergy is not well proven. I would ask him what he is referring to. IL2 is often a last ditch because of the toxicity associated with it, requiring a stay in the ICU etc.