NeurogesX Inc. reported the pain patch NGX-4010 met primary and secondary endpoints in a third Phase III trial, and the second in patients with postherpetic neuralgia.

The data will be added to an already-planned marketing authorization application filing expected later this year in Europe, while filing for approval in the U.S. will wait until data are in from an ongoing Phase III trial in HIV-associated distal sensory polyneuropathy. NeurogesX, of San Carlos, Calif., previously reported positive Phase III data in each indication, giving it three successful Phase III trials of the synthetic capsaicin-containing dermal patch.

"This study has important implications for us," said Anthony DiTonno, CEO of NeurogesX, who is working to secure a European marketing partner for the product. The company intends to establish its own specialty sales force in the U.S., where a new drug application filing is expected by the end of 2008.

In Europe, NeurogesX is seeking labeling for a broad indication of peripheral neuropathic pain, a labeling that would include painful diabetic neuropathy. DiTonno said that is by far the largest neuropathic pain indication. In Europe, he said, the completed studies would be enough to support the broader indication. In the U.S., however, guidelines are different, and the FDA would consider only the postherpetic neuralgia (PHN) and HIV-DSP indications, the ones for which the company has Phase III data.

DiTonno said NeurogesX plans to discuss those issues with the FDA and then move into clinical development in painful diabetic neuropathy, probably in the first half of 2008.

The newly reported Phase III trial evaluated NGX-4010, a TRPV1 agonist, in 416 PHN patients at sites in the U.S. and Canada. The C117 trial compared a single, 60-minute treatment with NGX-4010 to a control patch containing a low concentration of capsaicin. Patients were allowed to remain on their existing neuropathic pain medicines. Responses then were measured over a 12-week period.

The study demonstrated a 32 percent reduction in pain from baseline from weeks two to eight, compared to a 24 percent reduction in the control group (p=0.01), the trial's primary endpoint. Significant results also were achieved for study weeks two to 12 (p<0.02), a secondary endpoint. All other secondary endpoints, including 30 percent and 50 percent responder analyses, also were met.

PHN is a complication of shingles, a reactivation of the varicella zoster virus. Rash and blisters associated with shingles usually heal within six weeks, NeurogesX said, but some patients continue to experience pain for years. NeurogesX previously estimated there are about 1 million cases of shingles each year, with about 20 percent of them leading to postherpetic neuralgia.

DiTonno said discussions with potential European partners are ongoing, though they were slowed a little by vacation schedules there in July and August. The company plans to file for European approval later this year regardless of whether a partner is on board by then, he said.

For development in the U.S., the company has reported that the ongoing Phase III trial in 480 HIV-DSP patients was more than 90 percent enrolled. Data from that confirmatory study are expected in the first half of next year.

The high-concentration trans-capsaicin patch is designed so the TRPV1 agonist - or transient receptor potential vanilloid receptor (also called VR1) - is absorbed into the skin without significant absorption into the bloodstream, a mechanism designed to help avoid the systemic side effects of many other products.

The company, which raised $44 million in May in its initial public offering of shares at $11 apiece, has a lot riding on NGX-4010, since its next candidate has not entered full Phase I trials. That next-generation product is NGX-1998, a dermally delivered liquid formulation of synthetic capsaicin, for which an investigational new drug application filing is expected next year.

NeurogesX's stock (NASDAQ:NGSX) gained $1.14 Tuesday, or 16 percent, to close at $8.25.