** Sanofi, already benefiting from a weaker euro, up 1.5 pct and hits all-time high following promising data on Praluent, its experimental cholesterol drug being developed with Regeneron
** Clinical trial results with its product and a rival from Amgen suggest so-called PCSK9 inhibitors can reduce by half the risk of heart attack and other major cardiovascular problems compared to standard treatment alone
** Leerink analysts say PCSK9 results "continue to impress" and "we continue to warm to these agents", despite fact they have to be given as injections
** Regeneron shares up 1.5 pct in the U.S. pre-market (RM: ben.hirschler.thomsonreuters.com@reuters.net)