Addex Therapeutics (NASDAQ:ADXN) stock rallied 45% in morning trading Tuesday after the company announced it and partner Indivior (INDV) have selected clinical candidates from their GABAB positive allosteric modulator research collaboration.

Indivior has selected a compound for development as a treatment candidate for substance use disorder. Under the collaboration’s agreement, Addex will be eligible to receive up to $330M in milestone payments plus tiered royalties on net sales from the high-single digits up to low double-digits, according to a statement.

Addex added that it has selected a candidate to advance its own GABAB positive allosteric modulator program for the treatment of chronic cough.

Shares of Addex cratered in April after the company reported that a Phase 2 clinical trial for its epilepsy drug candidate ADX71149 had failed to meet its primary endpoint. Partner Johnson & Johnson (JNJ) informed Addex its was ending development of the drug for epilepsy in July.

Indivior shares were largely flat in late morning trading.