Real-World Utilization Of Blinatumomab In Acute Lymphoblastic Leukemia In The US

Abstract

Blinatumomab is the first bispecific CD19 directed CD3 T-cell engager immunotherapy to demonstrate overall survival benefit in patients with Philadelphia chromosome-negative (Ph-) relapsed/refractory acute lymphoblastic leukemia (ALL). In December 2014 the FDA granted an accelerated approval to blinatumomab in patients with Ph- relapsed/refractory B-precursor ALL based on findings from a phase II trial in 185 adults followed by the supplemental BLA approval to include new data in pediatric patients. Approved on 12/3/2014, blinatumomab is the first CD19 targeting bi-specific T-cell engagers (Bites) in the immuno-oncology arsenal. As it will likely compete with CD19 targeted CAR-T therapeutics, its uptake since approval may predict CAR-T potential in a similar clinical setting. Patients diagnosed with ALL on systemic therapy (ST) between 12/2014 and 12/2016 were identified from the Symphony Health claims database. Market share and time to treatment discontinuation (TTD) were examined. TTD was defined as time from ST initiation to switch or last administration date plus 90 days if no other ST was administered. TTD was described with Kaplan-Meier curves. Of the 18,162 ALL patients on ST since blinatumomab approval, 218 (1.2%) were treated with blinatumomab; of them 29 (13.3%) appeared to be Ph+ (indicated by utilization of nilotinib, ponatinib, dasatinib, imatinib, or bosutinib). The most common regimen was blinatumomab monotherapy followed by combination with methotrexate and/or cytarabine. Of the 218 patients treated with blinatumomab, 123 (56.4%) were male, 83 (38.1%) received blinatumomab in the first-line, and mean (SD) age was 43.9 (18.0) years. The mean (SD) number of prior antineoplastic regimens was 3.2 (3.6). Mean (median) TTD was 122.5 (110.0) days. This is the first real-world evidence study of blinatumomab and it demonstrates the uniqueness of the patient population for which it is currently indicated. CAR T-cell economic modeling should be informed by this research.