Objective: To examine the cost-effectiveness of using intrathecal ziconotide in the treatment of severe chronic pain compared to best supportive care for patients with intractable chronic pain in the United Kingdom.
Methods: Using a simulation model, the analysis evaluated the cost and health economic consequences of using ziconotide as a treatment for severe chronic pain. The modelled population and clinical data were based on a randomised controlled trial in which the main outcome was reduction in pain as measured by the visual analogue scale of pain intensity (VASPI). Resource use data were elicited using a modified Delphi panel and costed using published sources. Utility values were derived from a separate research study. The main outcome measure was the cost per quality-adjusted life-year (QALY). Extensive scenario analysis was conducted to evaluate parameter uncertainty.
Results: Overall, findings were robust to most assumptions. The cost-effectiveness of ziconotide compared to best supportive care (BSC) was pound 27,443 per QALY (95% CI pound 18,304-38,504). Scenarios were investigated in which discount rates, the time horizon, the threshold for qualifying as a responder, pump-related assumptions, utilities, ziconotide drug dose, and the patient discontinuation rate with ziconotide were varied. The most sensitive parameter was the dosage of ziconotide: using the lower and upper bounds of the average ziconotide dosage observed in the long-term open-label study changed the incremental cost-effectiveness ratio (ICER) to pound 15,500 [pound 8206-25,405] and pound 44,700 [pound 30,541-62, 670].
Conclusions: Ziconotide may offer an economically feasible alternative solution for patients for whom current treatment is inappropriate or ineffective. The main study limitation is that some model inputs, mainly related to resource use, are based on assumptions or expert interviews.