Addex Therapeutics Ltd (NASDAQ: ADXN) opened about 70% up this morning after making significant strides in its GABAB-positive allosteric modulator research. The clinical-stage pharmaceutical company has selected candidates for the PAM research that it’s undertaking in collaboration with Indivior PLC, as per a press release on Tuesday. Additionally, its UK-based partner picked a compound for the treatment of substance use disorder and assumed full responsibility of its future development as well. Despite today’s rally, Addex Therapeutics stock is down more than 50% versus its year-to-date high …