OBJECTIVES: Gene therapies promise new treatment options for diseases like Hemophilia B. While among the most expensive drugs in the world, conclusive evidence on (long-term) effectiveness is limited. Risk-sharing agreements aim to reduce financial risks to insurers paying for gene therapy but details on their implementation and success is scarce. Therefore, we simulate the impact of risk-sharing agreements on costs for insurers in Germany using the example of a Hemophilia B gene therapy.

METHODS: We developed a microsimulation state-transition model to simulate the long-term effectiveness of Etranacogene dezaparvovec for men with moderately severe to severe Hemophilia B from age 18 until their death. The disease progression was modelled around hemophilic arthropathy with transition probabilities based on bleeding rates. Costs were calculated on an individual level from the perspective of the German health care system using publicly available cost data. We simulated refund and multi-annual instalment agreements varying payment mechanisms, agreement duration, and treatment failure conditions.

RESULTS: We find larger cost saving potential to insurers with multi-annual instalment agreements during short timeframes of up to 5 years. For longer durations, this relationship reverses as savings from refund agreements increase over time while they decrease for multi-annual instalments. When considering the risk pool of the German health care system, we find that using multi-annual instalments increases costs for insurers leading to losses when compared to refund agreements as well as to the standard of care.

CONCLUSIONS: In an ideal setting, risk-sharing agreements provide an opportunity to reduce the costs of gene therapies for insurers and the choice of the specific agreement type is guided by aspects of affordability and personal risk preference, yet current regulatory frameworks in Germany limit the choice to refund agreements and may even restrict the adoption of new therapies if the choice is between standard of care and multi-annual instalments.