Background: Severe aplastic anemia (SAA) is a rare autoimmune condition resulting in low blood cell counts across lineages. Immunosuppressive therapy (IST) has demonstrated low response, toxicity, and risk of transformation. In a Phase I/II trial, the addition of eltrombopag to first-line IST increased response rates relative to an IST-only historical cohort.
Methods: A model was developed to estimate the budget impact of treating SAA with eltrombopag-based therapy from a US private healthcare system perspective. A simulated cohort of newly diagnosed SAA patients based on the total US population received 6 months of IST ± eltrombopag and were followed for 1 year, with mutually exclusive patient cohorts entering in years 1, 2, and 3. The model assessed the budget impact of first-year treatment for each cohort without considering subsequent years. At 6 months, responders in either arm received maintenance therapy (low-dose cyclosporine), and non-responders received 6 months of second-line eltrombopag monotherapy. Costs considered included first-line, maintenance, and second-line therapy, administration, routine care, mortality, and adverse events (AEs). All cost data were reported in 2018 US dollars.
Results: The annual incidence of aplastic anemia was 0.000234%, with 83.8% of cases assumed to be SAA. Based on trial data, 94% of patients receiving eltrombopag and IST responded versus 66% of patients receiving IST, with a 0.3% reduction in the annual risk of mortality for the eltrombopag + IST group. Use of first-line eltrombopag in a model SAA population based on the total US population increased overall costs by $50 million over 3 years. First-line drug costs accounted for an increase of $69 million, while improved response produced $19 million in secondary therapy cost savings. Sensitivity analyses confirmed the robustness of the analysis.
Conclusion: High response rates combined with reduced rescue medication use and mortality in patients treated with eltrombopag and IST mediated higher medication costs.
Keywords: United States; budget impact analysis; costs; eltrombopag; severe aplastic anemia; thrombopoietin receptor agonist.
© 2019 Tremblay et al.