Shares in Switzerland’s Addex Pharmaceuticals took a dip on the news that the firm is to discontinue development of its experimental smoking cessation treatment which has failed a mid-stage trial.

ADX10061, a dopamine D1 receptor antagonist originally discovered by Novo Nordisk which Addex licensed from the UK’s CeNeS in 2002, did not meet the primary efficacy endpoint in a Phase IIa trial which was four weeks continuous abstinence from the start of treatment week four. The drug failed to demonstrate a treatment effect compared to placebo so development has been stopped, said the Geneva-based firm which noted that similar trial designs and primary endpoints were used for the smoking cessation products already on the market, GlaxoSmithKline’s Zyban (bupropion) and Pfizer’s Champix (varenicline).

Addex said that it may evaluate other opportunities for ADX10061 in the future but “has no specific plans for the compound”. The firm’s share price ended the day down 3.9% to 50 Swiss francs but Addex noted that the failed drug is not related to its allosteric modulator technology on which the value of the company is primarily based.

Indeed, the firm stressed how well that technology has progressed, noting that its lead compound, ADX10059, for the treatment of gastroesophageal reflux disease and migraine, has successfully completed two Phase IIa trials. Nevertheless, the failure of ADX10061 is the first bit of bad news that Addex has suffered since May when it raised 137 million francs, or $111 million, in an initial public offering that was the largest biotech IPO in Europe for three years.