Background: Ziconotide is commonly used for intrathecal (IT) therapy of chronic pain, and has been recently indicated as a first-line IT drug. It is also extremely useful for patients intolerant or refractory to the common IT drugs (such as morphine). The literature, excluding registration studies, mostly includes small samples, and gives only fragmentary evidence on the long-term risks and benefits of ziconotide.
Objective: To collect data on safety and efficacy of long-term ziconotide IT infusion in Italian pain centers.
Study design: Retrospective cohort study on the use of ziconotide in Italy. The study was designed and coordinated by the Foundation ISAL (Algological Sciences Research and Training Institute). Patients treated with ziconotide from several pain therapy and neurosurgery units were included in the study, allowing the creation of the first Italian Registry of Ziconotide.
Setting: Seventeen Italian public and private pain and neurosurgery centers.
Methods: Patients suffering from cancer or non-cancer intractable chronic pain who had been treated with ziconotide IT infusion for at least one month. Efficacy was analyzed considering changes on the visual analog scale of pain intensity from baseline observation. Safety was assessed by monitoring the number and intensity of adverse events.
Results: Currently, 104 patients are included in the Italian Registry of Ziconotide. Ziconotide was administered as the first IT drug choice to 55 patients. Seventy-two patients reported at least a 30% pain intensity reduction with a mean dose of 4.36 ug/d. The sustained analgesic effect (P < 0.001) of the ziconotide IT therapy was observed in a group of 45 patients who remained in the study over 6 months without treatment interruptions and with relatively stable doses. Sixty-six patients reported at least one side effect related to ziconotide. However, adverse events have not always been decisive for treatment interruptions.
Limitations: Data were collected retrospectively from different pain centers that used different methods for ziconotide treatment and clinical forms for its data collection; for this reason there is an absence of standardized methodologies and a placebo-controlled group, and some data were missing.
Conclusions: Ziconotide IT therapy is a treatment option commonly used for clinical practice in 17 Italian pain therapy and neurosurgery units. It might give relief to patients with refractory chronic pain, and it seems to have a safe profile. Long-term studies and controlled trials are required.