Citi analyst Andrew Baum said he believes AbbVie's (ABBV) roughly $2B synergies target for its deal with Allergan (AGN) looks achievable and he thinks the takeover plugs the Humira revenue hole and likely generates long term sustainable growth through Allergan's aesthetic franchise. While he is "more relaxed" about longer-term risks, including AbbVie's potential to underinvest or mismanage the aesthetics business or erosion of Botox market share, he sees near-term risks that include the impact of a potential U.S. Enbrel biosimilar launch on Humira revenues, and therefore AbbVie's credit rating, as well as Allergan's near-term non-GAAP outlook given the company's "poor guidance track record." Baum keeps a Neutral rating on AbbVie shares.