OBJECTIVES : Inotuzumab ozogamicin (InO) and blinatumomab (Blina) are therapies approved for relapsed/refractory acute lymphoblastic leukaemia (rrALL). InO and Blina were associated with higher response and survival compared to standard of care (SoC) chemotherapy in their trials, and InO was also associated with higher hematopoietic stem cell transplantation (HSCT) rates; hence, InO and Blina use is likely to increase over time. We modelled the budget impact of increasing market shares of InO and Blina in the Netherlands.

METHODS : A budget impact model with a 5-year time horizon including treatment, adverse events, hospitalization, HSCT, and end-of-life costs was developed. The eligible annual population was 20 patients. It was assumed InO, Blina and FLAG-Ida (SoC) each cover one-third of the market. This base case was compared to two scenarios where 1) only InO is used, and 2) only Blina is used. Subsequently, the budget impact of scenario 1 versus 2 was determined. Dutch cost inputs for 2020 were based on the Z-Index, previous ALL economic evaluations, the Dutch costing manual, and literature. Recent real-world hospitalization data was used for InO and FLAG-Ida.

RESULTS : When all therapies are used equally, Blina is associated with the highest average total costs at €1.83 million annually; InO was less at €1.77 million and FLAG-Ida at €1.03 million (total: €4.63 million). In scenarios 1 and 2, where either only InO or Blina was used, average annual costs were €5.31 and €5.49 million, respectively. The corresponding budget impact versus the base case was €0.68 and €0.86 million per year. The 5-year cumulative budget savings from treating all patients with InO instead of Blina is €0.9 million, rising to €6.1 million saved when HSCT-related costs are excluded.

CONCLUSIONS : Blina was associated with the highest annual costs. Treating every patient with InO over Blina potentially saves €6.1 million pre-HSCT over 5 years.