We are developing a transdermal bupivacaine patch (ELADUR) based on our proprietary TRANSDUR transdermal technology intended to provide continuous delivery of bupivacaine for up to three days from a single application, as compared to a wearing time limited to 12 hours with currently available lidocaine patches. We anticipate that ELADUR will have several potential differentiating attributes compared with currently marketed lidocaine patches, including extended duration of action and better wearability.

Market Opportunity
Pain can arise from a variety of diseases and conditions, and in many instances, pain originates from a localised point in the body and can benefit from treatments which are administered and act locally as opposed to in a systemic fashion.

In September 2008, we entered into a development and license agreement with Alpharma Ireland Ltd., an affiliate of Alpharma, Inc., granting such party the exclusive worldwide rights to develop and commercialize ELADUR. This agreement became effective in October 2008 after passing clearance under the Hart-Scott-Rodino Antitrust Improvements Act of 1976. Under this agreement, Alpharma paid us an upfront license fee of $20 million in the fourth quarter of 2008, with possible additional payments of up to $93 million upon the achievement of predefined development and regulatory milestones spread over multiple clinical indications and geographical territories as well as possible additional payments of up to $150 million in sales based milestones. If ELADUR is commercialized, DURECT would also receive royalties on product sales. Alpharma will control and fund the further development program. Alpharma was acquired by King Pharmaceuticals in December 2008 and, as a result, the rights and obligations of our agreement were controlled by King. King was acquired by Pfizer in February 2011 and, as a result, the rights and obligations of our agreement are now controlled by Pfizer.

Expected Product Benefits:

• Longer duration of action, as compared to the 12 hours of relief provided with currently available lidocaine patches;
• Fast onset time;
• Potentially deeper tissue penetration of bupivacaine versus lidocaine patches.

Current Clinical Status
This investigational drug is currently in Phase II. Phase II results are not necessarily predictive of the results of Phase III trials. There have been numerous drug candidates that have succeeded in Phase II clinical trials that have later failed in Phase III clinical trials.

In 2007, we successfully completed a 60 patient Phase IIa clinical trial for ELADUR. In this study of patients suffering from PHN, ELADUR showed improved pain control versus placebo during the 3-day continuous treatment period. In addition, ELADUR appeared well tolerated overall, and patients treated with ELADUR and placebo exhibited similar safety profiles. In April 2011, we reported top-line results from a Phase II clinical trial in chronic low back pain for ELADUR. This study was conducted by our collaborator, King Pharmaceuticals, which is now owned by Pfizer. In this study of 263 patients suffering from chronic low back pain, the primary efficacy endpoint of demonstrating positive treatment difference for the mean change in pain intensity scores from baseline to the mean of weeks 11 and 12 between ELADUR as compared to placebo was not met. We and Pfizer are continuing to analyze this most recent study and will work together to determine next steps.

To review data on ELADUR reported at the American Pain Society 27th Annual meeting, click here.