I'll probably disappoint you guys because I don't know much about figuring out entry point and I don't pretend to know. What I do know is don't be afraid to buy high and sell higher. So long term investor shouldn't miss this opportunity just because they want to wait for another pull back. For traders, you might've missed the first half of the recovery, but there's still some room to run, and I don't see anything keeping it down in the forseeable future. CELG has a PEG ratio less than 1, and a very diversified drug pipeline (just check its pipeline on Celgene website).
A caveat, Gilead, the bastard that dragged the whole bitoech sector to the mud 2 months ago, was in the red last Friday, partially due to Sovaldi prescription, but it was also because its pricing practice was under scrutiny again. This is all too familiar which is why I'm neutral (I bot some shares at 145 and bot some July DTM calls 130 at 20 last week, sold all my shares today but kept my calls), or maybe I'm just being paranoid, but again, you can never be too careful in this market.