Shares in NicOx have taken a battering on the news that partner Pfizer has chosen not to take the French biotechnology firm’s investigational glaucoma drug into late-stage trials.

The stock ended the day down 28% at 10.45 euros after NicOx announced diappointing results from a US Phase II study, conducted by Pfizer, which compared the safety and efficacy of various doses of PF-03187207, a nitric oxide-donating prostaglandin analogue, to the latter’s own Xalatan (latanoprost) in patients with primary open-angle glaucoma and ocular hypertension. On the primary endpoint at 28 days, PF-03187207 showed a 12% improvement over Xalatan 0.005% but this was not statistically significant.

NicOx said that a statistically significant advantage over Xalatan 0.005% was observed “on a number of secondary endpoints”, but Pfizer has still decided to pull the plug. David Eveleth, vice president of ophthalmology development at the New York-based behemoth, said that the Phase II study
“has provided interesting data” but the study “did not meet its primary clinical endpoint and our criteria for launching a global Phase III programme”. However he said that the firm remains committed to its partnership with NicOx (the companies have been collaborating since March 2006), saying that “follow-up compounds to PF-03187207 have produced encouraging results”.

Pfizer is currently conducting a Phase II study for PF-03187207 in Japan and has indicated that it would consider continuing the development of the drug for potential registration in Asia, including Japan, depending on the results which are expected in the third quarter of this year. The two firms are in discussions regarding the rest-of-world rights.

NicOx chief executive Michele Garufi was upbeat about the data, saying that they suggest nitric oxide donation “can bring therapeutic benefit through improved intraocular pressure lowering”. He added that “we believe this Phase II study demonstrates a clear commercial potential for PF-03187207 and we are exploring possible strategies with Pfizer to unlock this value”.