UPDATE 1-Astra gets lift in Pfizer fight as U.S. okays heart pill
* Epanova approved to reduce triglyceride levels * AstraZeneca acquired drug after buying Omthera in 2013 * Sales seen at $322 mln by 2018 - consensus forecast (Adds details on drug, sales forecast, background) By Ben Hirschler LONDON, May 6 (Reuters) - AstraZeneca Plc h
