Carlsbad-based Regulus Therapeutics, the joint venture between Alnylan Pharmaceuticals and Isis Pharmaceuticals, said today that it has appointed Kleanthis G. Xanthopoulos as its President and CEO. Xanthopoulos joins the firm from Enterprise Partners Venture Capital, where he was a managing director. Xanthopoulos was a co-founder, President, and CEO of Anadys Pharmaceuticals before he became a venture capitalist at Enterprise. Xanthopoulos had joined Enterprise in June of 2006.