Cost Effectiveness of Blinatumomab Versus Inotuzumab Ozogamicin in Adult Patients with Relapsed or Refractory B-Cell Precursor Acute Lymphoblastic Leukemia in the United States

BACKGROUND AND OBJECTIVE: The TOWER and INO-VATE-ALL trials demonstrated the efficacy and safety of blinatumomab and inotuzumab ozogamicin (inotuzumab), respectively, versus standard-of-care (SOC) chemotherapy in adults with relapsed or refractory (R/R) B-cell precursor acute lymphoblastic leukemia (ALL). The cost effectiveness of blinatumomab versus inotuzumab has not previously been examined. METHODS: Cost effectiveness of blinatumomab versus inotuzumab in R/R B-cell precursor ALL patients with one or no prior salvage therapy from a United States (US) payer perspective was estimated using a partitioned survival model. Health outcomes were estimated based on published aggregate data from INO-VATE-ALL and individual patient data from TOWER weighted to match patients in INO-VATE-ALL using matching adjusted indirect comparison (MAIC). Analyses were conducted using five approaches relating to use of anchored versus unanchored comparisons of health outcomes and, for the anchored comparisons, the reference treatment to which treatment effects on health outcomes were applied. Estimates from TOWER including the probabilities of complete remission and allogeneic stem-cell transplant (allo-SCT), overall and event-free survival, utilities, duration of therapy, and use of subsequent therapies were MAIC adjusted to match INO-VATE-ALL. Costs of treatment, adverse events, allo-SCT, subsequent therapies, and terminal care were from published sources. A 50-year time horizon and 3% annual discount rate were used. RESULTS: Incremental costs for blinatumomab versus inotuzumab ranged from US$7023 to US$36,244, depending on the approach used for estimating relative effectiveness. Incremental quality-adjusted life-years (QALYs) ranged from 0.54 to 1.78. Cost effectiveness for blinatumomab versus inotuzumab ranged from US$4006 to US$20,737 per QALY gained. CONCLUSIONS: Blinatumomab is estimated to be cost effective versus inotuzumab in R/R B-cell precursor ALL adults who have received one or no prior salvage therapy from a US payer perspective. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s40273-019-00812-6) contains supplementary material, which is available to authorized users.