OBJECTIVES: To evaluate the cost-utility and budget impact of C1-esterase inhibitor for long-term prophylaxis in patients with hereditary angioedema (HAE) type I and II from the healthcare system perspective of Kazakhstan.

METHODS: The analysis compared no prophylaxis versus C1-esterase inhibitor (Cinryze) prophylaxis for prevention of attacks. A previously published Markov model, including 2 states and a decision tree for attack pathways, was adapted to the Kazakhstan setting. National Diagnosis-Related Group tariffs were applied for estimate direct costs. The model used a 5-year time horizon and monthly steps. Probabilistic sensitivity analysis (PSA) was conducted to explore the effect of parameter uncertainty on the results. The cost-utility model was used to construct a 5-year budget impact model assuming HAE prevalence in the general population at 1 in 67 000.

RESULTS: In the base case scenario, the prophylaxis strategy resulted in 5-year incremental costs of 100.97 million Kazakhstani tenge (₸) (equivalent to 743 986 international dollars (Int$) using the 2019 PPP conversion factor) and 0.17 incremental quality-adjusted life-years (QALY). The incremental cost-utility ratio (ICUR) was estimated at 592.06 million ₸ (4.36 million Int$) per QALY gained. Over 1000 PSA iterations, the median ICUR was 592.96 million ₸ (interquartile range 554.08 - 636.64 million ₸). The estimated budget impact ranged from 2.023 billion ₸ (14.9 million Int$) in the first year to 1.956 billion ₸ (14.4 million Int$) in the fifth year.

CONCLUSIONS: The analysis suggests that the long-term prophylaxis strategy would incur considerable costs far above any conventional thresholds, as expected for an orphan drug. The results are comparable with previous assessments. Since clinical parameters were largely informed by data from one clininal trial, the model interpretability in the context of real-world long-term prophylaxis is debatable. More country-specific data may be needed to more reliably evaluate potential long-term outcomes in HAE patients.