NeurogesX Extension Study Indicates Repeat Treatment with Transacin Provides Prolonged Pain Reduction in HIV-Associated Neuropathy; Company Initiates Confirmatory Pivotal Phase 3 Study in Painful HIV-Associated Neuropathy

Business Wire, Sept 6, 2006

SAN CARLOS, Calif. -- NeurogesX, Inc., a privately held specialty pharmaceutical company, presented results from an open-label 40-week extension study in painful HIV-associated neuropathy (HIV-AN) patients that indicated repeat treatment with Transacin(TM) (NGX-4010) resulted in consistent reductions in pain over the entire 52-week study period. The magnitude of response to the open-label Transacin treatments was comparable to the response observed during the 12-week controlled portion of the study. Long-term use of Transacin was well tolerated without evidence of cumulative toxicity. NeurogesX has initiated a confirmatory pivotal Phase 3 multi-center, randomized, double-blind, controlled study with Transacin in 480 patients with HIV-AN.

Results from the open-label extension study with Transacin in HIV-AN were presented at the XVI International AIDS Conference (AIDS 2006) in Toronto, Canada held earlier this month. Results from the randomized, double-blind, controlled portion of this study, which were previously presented in February 2006 at 13th Conference on Retroviruses and Opportunistic Infections, showed a statistically significant reduction in pain (p = 0.0025) that was sustained over the 12-week study period following a single administration of Transacin.

"This study suggests that Transacin can provide long-term benefit to patients with painful HIV-AN with a one-hour application every three to four months," said David Simpson, M.D., Professor of Neurology at Mount Sinai School of Medicine in New York and lead academic investigator in the NeurogesX study. "Because Transacin is a local treatment, it is not expected to produce systemic side effects or have drug-drug interactions, which is particularly important in this patient population." Transacin related adverse events were comprised of self-limited, local application site reactions.

"We are excited to report that our confirmatory pivotal study in HIV-AN with Transacin is now underway," said Anthony A. DiTonno, NeurogesX President and CEO. "HIV-AN represents an important underserved market opportunity for NeurogesX as there are no currently approved therapies for this patient population. We expect that HIV-AN will be a cornerstone of our new drug application (NDA) filing." Transacin has been granted orphan drug and fast track status for HIV-AN by the U.S. Food and Drug Administration.

Additional information about NeurogesX's confirmatory pivotal Phase 3 HIV-AN is available at http://www.clinicaltrials.gov/ct/show/NCT00321672?order=6. This trial is being conducted internationally, with sites in Australia, Canada, the United Kingdom and the United States.

About Transacin (NGX-4010)

Transacin is a topical, physician administered patch containing a high concentration of trans-capsaicin, a synthetic form of the naturally occurring TRPV1 agonist capsaicin. Unlike current treatment approaches for neuropathic pain that include opioids and other agents acting on the central nervous system that can cause drowsiness or other systemic side effects, the patch is designed to act peripherally in the skin, where the pain frequently originates. Due to the novel patch delivery system and dermal site of action of Transacin, the potential for safety issues or side effects that negatively impact quality of life is expected to be low.

About NeurogesX

NeurogesX is a privately held specialty pharmaceutical company focused on the development of novel treatments for the management of neuropathic pain. The company's initial products are focused on the treatment of chronic pain in the areas of postherpetic neuralgia (PHN), painful HIV-associated neuropathy (HIV-AN) and painful diabetic neuropathy (PDN). NeurogesX intends to file for marketing approval in Europe in the first half of 2007 and plans to file an NDA in the United States in 2008. Additional information about NeurogesX can be found at www.neurogesx.com.

NeurogesX is a trademark of NeurogesX, Inc.