Genzyme Breaking Out

What happened to Genzyme (GENZ)? I went up $2.69 to close at a new high of $62.71, a 4.40% gain, on big volume. I can't figure out the reason for this move. The only press release today was some Synvisc news, which shouldn't have affected the stock price. Yesterday, they announced an acquisition of Bone Care International (BCII). This is a good strategic deal, but it will only be slightly accretive to earnings in 2006. The acquisition news was already reflected in yesterdays stock price. I'm not complaining since this is my largest position. But something's up...