Pfizer will not pursue phase 3 study of experimental glaucoma treatment in Asia

SOPHIA ANTIPOLIS, France — Pfizer has decided not to launch a phase 3 development program for an experimental glaucoma treatment in Asia, NicOx announced in a press release.

Pfizer's dose-ranging phase 2 study compared the safety and efficacy of PF-03187207, a nitric oxide-donating prostaglandin, with Xalatan (latanoprost 0.005%, Pfizer) among 112 Japanese patients with primary open-angle glaucoma or ocular hypertension. Pfizer and NicOx are co-developers of the drug.

At 28 days follow-up, the two highest doses of PF-03187207 had yielded up to 11% more reduction in diurnal IOP than latanoprost, the release said. However, while the drug appeared safe and well-tolerated with mild adverse events, the study failed to demonstrate the novel compound's ability to significantly reduce elevated diurnal IOP more than latanoprost.

This follows the May announcement of results from Pfizer's dose-ranging phase 2 study of the drug in the United States. While the highest dose of PF-03187207 showed a 12% improvement over latanoprost at day 28, the difference also failed to reach statistical significance, according to the release.

However, in both the Japanese and U.S. studies, PF-03187207 demonstrated a 20% greater reduction in IOP at 20 hours after dosing compared with latanoprost; the reduction reached statistical significance in the U.S. study, the release said.

NicOx and Pfizer are currently negotiating the global rights to develop and commercialize PF-03187207 under the terms of their 2004 agreement. The companies plan to focus on an ongoing program to identify nitric oxide-donating compounds for treating diabetic retinopathy, with the goal of selecting a lead compound for development during the first half of 2009.

In addition, Pfizer has decided to conclude all further research concerning nitric oxide-donating prostaglandin analogs covered under the agreement.