Elan Corporation plc has submitted an amendment to its New Drug Application (NDA) to the US FDA for approval of Prialt (ziconotide) for the treatment of severe chronic pain. The company anticipates a review time of approximately six months, a company release said.

This amendment to the original NDA incorporates results from the most recent phase III trial, which demonstrated a statistically significant result with Prialt, at lower doses and following a slower titration schedule than had been studied in prior double-blind trials. Elan will not disclose detailed findings from this phase III study until the FDA has reviewed them. The company plans to present these data at a major scientific meeting.

"We are encouraged about the new findings, which complement the data from the previously disclosed trials," said Lars Ekman, executive vice president, and president Research and Development, Elan. "The total clinical database on Prialt represents one of the most comprehensive bodies of research on intrathecal pain management to date, and is evidence of Elan's sustained commitment to patients with severe chronic pain who desperately need additional treatment options," he said.

The FDA had previously issued an approvable letter for Prialt, in which the agency requested additional information. A third trial was conducted in response to the FDA's request for an additional clinical study. This trial evaluated the efficacy and safety of lower doses of Prialt and a slower titration schedule than was used in two previous phase III studies. The study met its primary endpoint of a significant improvement on the Visual Analog Scale of Pain Intensity in the Prialt group as compared to the placebo group.

Prior double-blind studies have also indicated benefit in patients with severe chronic pain related to cancer, AIDS, or non-malignant causes. The most commonly reported adverse events among patients receiving Prialt in the latest trial were dizziness, nausea, asthenia, somnolence, diarrhea, and confusion.

Prialt is the first drug in a new class of non-opioid analgesics called N-type calcium channel blockers (NCCBs), administered intrathecally (directly into the fluid surrounding the spinal cord through a surgically implanted catheter), for the treatment of severe chronic pain.