A health-economic analysis of porcine islet xenotransplantation.

BACKGROUND

Islet cell transplantation is a promising treatment for type 1 diabetes. To overcome the shortage of deceased human pancreas donors, porcine islet cell xenotransplantation is being developed as an alternative to allotransplantation. The objective of this study was to perform a cost-effectiveness analysis of porcine islet transplantation in comparison with standard insulin therapy. The patient population for this study was young adults, ages 20 to 40, for whom standard medical care is inadequate in controlling blood glucose levels (hypoglycemia unawareness). Since trial data were lacking, estimates used extrapolations from data found in the literature and ongoing trials in clinical allotransplantation. Cost estimates were based on the data available in the USA.

METHODS

Markov modeling and Monte Carlo simulations using software specifically developed for health-economic evaluations were used. Outcomes data for ongoing clinical islet allotransplantation from the University of Minnesota were used, along with probabilities of complications from the Diabetes Control and Complications Trial. Quality-adjusted life years (QALYs) were the effectiveness measure. The upper limit of being cost-effective is $100,000 per QALY. Cost data from the literature were used and adjusted to 2007 US dollars using the medical care portion of the Consumer Price Index.

RESULTS

In both Markov modeling and Monte Carlo simulations, porcine islet xenotransplantation was both more effective and less costly over the course of the 20-yr model. For standard insulin therapy, cumulative cost per patient was $661,000, while cumulative effectiveness was 9.4 QALYs, for a cost of $71,100 per QALY. Transplantation had a cumulative cost of $659 000 per patient, a cumulative effectiveness of 10.9 QALYs, and a cost per QALY of $60,700. Islet transplantation became cost-effective at 4 yr after transplantation, and was more cost-effective than standard insulin treatment at 14 yr. These findings are related to relative high costs in the transplantation arm of the evaluation during the first years while those in the insulin arm became higher later in follow-up. Throughout the follow-up period, effectiveness of transplantation was higher than that of insulin treatment. In sensitivity analysis, duplication or triplication of one-time initial costs such as costs of donor animal, islet manufacturing and transplantation had no effect on long-term outcome in terms of cost-saving or cost-effectiveness, but the outcome of transplantation in terms of diabetes complications in cases with partial graft function could affect cost-saving and cost-effectiveness conclusions.

CONCLUSION

Despite limitations in the model and lack of trial data, and under the assumption that islet transplantation outcomes for young adult type 1 diabetes patients are not dependent on the source of islet cells, this health-economic evaluation suggests that porcine islet cell xenotransplantation may prove to be a cost-effective and possibly cost-saving procedure for type 1 diabetes compared to standard management.