Every drug company has patents exparing these days. I think the very low p/e of 8 or so kind of taking care of these.
One needs to notice that these patents are coming off over the coming 3-4 years or so. The good thing with AZN is, this company will launch 5-10 potenital multi-billion dollar drugs over the same time horizen. Therefore, the upside potential is with this stock.
I would think, AZN at p/e 8, is a great buy, when both the positives and the nagatives are considerred.