Objectives. The study aims to assess the safety and efficacy of intrathecal (IT)
ziconotide when delivered via an external infusion system. Materials and Methods. Patients with severe
chronic pain were implanted with an external infusion system, and IT
ziconotide was titrated over one to four weeks. Safety was evaluated via adverse event (AE) reports, and efficacy measures included the visual analog scale of
pain intensity (VASPI), categorical
pain relief scale (CPRS), and clinical global impression (CGI). Results. Sixty-four of the 71 patients (90.1%) experienced an AE during titration; five patients developed
meningitis after completing at least two weeks of
therapy. A significant (p ≤ 0.005) median percentage improvement in VASPI scores was seen at week 1 and maintained through week 4 (range: 11.0-32.6%); 53.6% of patients reported good to excellent
pain control on the CGI and 52.2% of patients reported moderate to complete
pain relief on the CPRS. Conclusions. The study results suggest that a short-term trial of IT
ziconotide using an external infusion system may be sufficient to assess patient response. High rates of AEs were noted; however,
ziconotide-related AEs were consistent with those reported in previous trials.