Zogenix, Inc. announced the completion of enrolment in its pivotal phase 3 efficacy study (Study 801) of ZX002. ZX002 is a novel, oral, single-entity, controlled-release formulation of hydrocodone for the treatment of moderate to severe pain in patients requiring around-the-clock opioid therapy for an extended period of time.

Study 801 is a randomized, 12-week, double-blind, placebo-controlled trial evaluating ZX002 in opioid-experienced adult subjects with moderate to severe chronic lower back pain. The primary efficacy endpoint is the mean change in average daily pain intensity scores between ZX002 and placebo.

Initial top-line data from Study 801 and an open-label Phase 3 safety study (Study 802) are anticipated to be available during the second half of 2011. As previously announced, Zogenix has completed enrolment of Study 802 to evaluate overall safety of ZX002 in patients for up to one year.

Pending positive phase 3 clinical results, Zogenix expects to submit an NDA for ZX002 with US Food and Drug Administration (FDA) by early 2012. If approved, ZX002 has the potential to be the first controlled-release version of hydrocodone and also the first hydrocodone product that is not combined with another analgesic. This novel formulation has the potential to address safety concerns outlined by the FDA regarding the use of certain combination prescription pain products that contain acetaminophen, which can cause liver toxicity at high doses over time. In January 2011, the FDA announced that manufacturers of certain prescription pain products containing acetaminophen will be required to reformulate or discontinue making these products within three years.

Stephen J. Farr, Ph.D., president and chief operating officer said, "After completing enrolment in both phase 3 studies, ZX002 remains positioned as the first potential single-entity, controlled-release hydrocodone product. Since it does not contain acetaminophen and allows for convenient twice daily dosing, ZX002 may fulfil a beneficial treatment option for both patients using immediate-release hydrocodone combination products on a chronic basis and an alternative for patients already using extended-release opioids for the management of their moderate to severe pain. We look forward to obtaining top-line safety data from Study 802 and efficacy and safety data from Study 801 during the second half of this year to support a potential NDA submission by early-2012."

Nathaniel P. Katz, M.D., Adjunct Assistant Professor of Anaesthesia at Tufts University School of Medicine, said, "In light of the recent FDA decision and the public concern over the risks of liver toxicity associated with high doses of acetaminophen, having a new medication option of hydrocodone without the combination of acetaminophen will be an important addition to the management and care of chronic pain."

The American Pain Society estimated in 1999 that 9% of the US adult population suffers from moderate to severe non-cancer related chronic pain. Chronic pain can be treated with both immediate-release and extended-release opioids. Marketed hydrocodone products are the most commonly prescribed pharmaceuticals in the United States, generating $3.1 billion in US sales during the 12 months ended June 2010 (Wolters Kluwer Pharma Solutions, Source: PHAST Retail). All of these hydrocodone products contain an analgesic combination ingredient, primarily acetaminophen. When used in high dosages over time, acetaminophen can cause liver toxicity.

ZX002 is a novel, oral, single-entity controlled-release formulation of hydrocodone currently in phase 3 clinical trials for the treatment of moderate to severe chronic pain in patients requiring around-the-clock opioid therapy for an extended period of time. ZX002 uses Elan Pharma International Limited's proprietary Spheroidal Oral Drug Absorption System, or SODAS Technology. The SODAS technology serves to enhance the release profile of hydrocodone to provide consistent 12-hour pain relief relative to existing immediate-release combination formulations.

If approved, ZX002 may represent the first available controlled-release version of hydrocodone and also the first hydrocodone product that is not combined with another analgesic. The phase 3 clinical development program for ZX002 was initiated in March 2010 and initial top-line data are anticipated in the second half of 2011. Pending positive Phase 3 clinical results, Zogenix expects to submit a new drug application (NDA) for ZX002 with US Food and Drug Administration (FDA) by early 2012.

Zogenix, Inc. with offices in San Diego and Emeryville, California, is a pharmaceutical company commercializing and developing products for the treatment of central nervous system disorders and pain.