** UK-based drugmaker's shares up 4.4 pct at 1,550.5pence on the London Stock Exchange; stock top gainer on FTSE 100
** U.S.-listed shares up 4 at $47.61 premarket
** UBS raises its rating to "buy" from "sell", saying itexpects new products sees strong growth. Also raises pricetarget to 1700p from 1250p
** UBS analysts say they see, for the first time in over adecade, scope for substantial earnings growth in the coming 3-5years, driven by new vaccines and AIDS drugs
** Up to Thursday's close, company's stocks had fallen 10pct in London and 15 pct in New York in the past 12 months