Swiss biotech group Addex (ADXN.S) is aiming to strike a partnership for its experimental Parkinson’s disease drug by the end of this year and has been in talks with several companies, the group’s chief executive told Reuters on Thursday. The drug, dipraglurant, which has just met its main goals in a mid-stage study, could rake in sales of $1 billion, CEO Bharatt Chowrira said. At 1243 GMT, Addex shares were up 54.8 percent, easily outperforming the rest of the European healthcare market and adding to the 16 percent gained so far this year. The shares had earlier traded as high as double their Wednesday close.