Health-Related Quality of Life of Blinatumomab for Relapsed or Refractory B-Cell Precursor Acute Lymphoblastic Leukemia in a Randomized, Open-Label Phase 3 Study (TOWER): A Subgroup Analysis By Prior Allogeneic Hematopoietic Stem Cell Transplantation

Abstract

Background In the phase 3 TOWER study, patients with relapsed or refractory (r/r) Ph– B-cell precursor (BCP) acute lymphoblastic leukemia (ALL) who received blinatumomab had longer overall survival and improved health-related quality of life (HRQoL) versus patients who received standard of care chemotherapy (SOC). Because ALL patients who relapse from previous hematopoietic stem cell transplantation (HSCT) have poorer prognosis, we analyzed the HRQoL of TOWER patients with or without prior allogeneic HSCT (alloHSCT). Methods Adults (n=405) with r/r Ph– BCP ALL were randomized 2:1 to 2 cycles of induction blinatumomab (n=271) or SOC (n=134), followed by up to 3 consolidation cycles; 12 months of maintenance was allowed. AlloHSCT was allowed after cycle 1. HRQoL was assessed in cycle 1 (days 8, 15, and 29) using the EORTC QLQ-C30 Questionnaire. For global health status and functioning scales, a higher score indicates better HRQoL; for symptom scales/items, a lower score indicates better HRQoL. Time to deterioration analyses assessed the treatment effect based on a 10-point deterioration (clinically significant threshold) from baseline. Results Of 342 evaluable patients (blinatumomab, n=247; SOC, n=95); 114 (blinatumomab, n=85; SOC, n=29) and 228 (blinatumomab, n=162; SOC, n=66) did and did not, respectively, have prior alloHSCT. In those with no prior alloHSCT, changes in global health status were minimal for blinatumomab and SOC (Figure 1). In contrast, in patients with prior alloHSCT, global health status modestly improved in the blinatumomab group but worsened by ≥10 points at all time points for SOC, indicating clinically meaningful deterioration. Changes in functioning scales were minimal in the blinatumomab arm, both with or without prior alloHSCT, except for relatively improved emotional scores in patients with prior alloHSCT. In contrast, SOC patients had worsening in most functioning scales, regardless of prior alloHSCT status. This effect was most marked in those with prior alloHSCT, in whom physical, role, and social functioning deteriorated by ≥10 points. Similar patterns were observed for symptom scales/items: while blinatumomab was associated with improved or less worsening in symptom scores versus SOC, most symptom scores worsened in the SOC arm, especially in patients with prior alloHSCT, for whom all symptoms (except dyspnea) deteriorated by ≥10 points. Compared with SOC, blinatumomab was associated with a delayed time to clinically meaningful deterioration, particularly in patents with prior alloHSCT (Figure 2). Conclusions In patients with r/r Ph– BCP ALL, blinatumomab was associated with improved HRQoL compared with SOC, regardless of whether patients had received prior alloHSCT. Notably, however, the HRQoL benefit of blinatumomab was most pronounced among patients with prior alloHSCT.