Durect has reported unsuccessful results from a Phase II clinical trial evaluating Eladur (transdur-bupivacaine), Durect’s proprietary investigational transdermal bupivacaine pain patch, in patients with chronic low back pain.

The Phase II study enrolled 263 patients suffering from chronic low back pain.

The study failed to meet the primary efficacy endpoint, which was defined as a 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.

The study was conducted by Durect’s collaborator, King Pharmaceuticals, which is now owned by Pfizer.

Eladur had demonstrated a positive efficacy trend in a Phase 2a study for post-herpetic neuralgia (PHN).

Eladur is an investigational transdermal drug patch intended to deliver bupivacaine for up to three days from a single application.

Bupivacaine, the active agent in Eladur, is a local anaesthetic approved by the US Food and Drug Administration (FDA) and is used in regional anesthesia for local tissue infiltration, nerve block, and epidural and intrathecal anaesthesia.