CML-353: Health Care Resource Utilization (HCRU) with Asciminib and Bosutinib among Patients with Chronic Myeloid Leukemia in Chronic Phase (CML-CP) Previously Treated with ≥2 Tyrosine Kinase Inhibitors (TKIs): Results from the Multicenter, Open-Label Phase 3 ASCEMBL Trial

Abstract

Objective: To investigate HCRU among CML-CP patients who received asciminib or bosutinib after previously being treated with ≥2 TKIs in a clinical trial setting. Design: ASCEMBL enrolled adults with CML-CP who had previously been treated with ≥2 TKIs. Patients were randomized in a 2:1 ratio to receive asciminib 40 mg twice daily (n=157) or bosutinib 500 mg once daily (n=76). Data were collected while on randomized treatment for the following HCRU categories: hospitalizations, emergency hospital visits, general practitioner visits, specialist visits, and urgent care visits. The reasons (adverse events, CML, and other) for accessing services were also captured. The number of patients in each arm with any HCRU, by category, was calculated and used to estimate rates per patient-year. Main Outcomes Measures: Median exposure to treatment; number of patients with HCRU, by category; rate of HCRU per patient-year. Results: As of the 25 May 2020 cut-off, the median duration of exposure was 43.4 and 29.2 weeks in the asciminib and bosutinib arms, respectively. In the asciminib arm, 24.2% (n=38) had HCRU compared to 36.8% (n=28) of those who received bosutinib, corresponding to rates per person-year of 0.32 and 0.80. The percentage of patients (and rates per person-year) with HCRU by category for asciminib and bosutinib were 14.0% (0.16) versus 18.4% (0.32) for hospitalizations, 1.9% (0.02) versus 5.3% (0.08) for emergency hospital visits, 4.5% (0.05) versus 6.6% (0.11) for general practitioner visits, 10.8% (0.13) versus 13.2% (0.24) for specialist visits, and 0% (0) versus 5.3% (0.08) for urgent care visits. A higher percentage of patients treated with bosutinib compared to asciminib required hospitalization (7.9% [n=6] versus 1.9% [n=3]) or a visit to a hospital emergency department (2.6% [n=2] versus 1.3% [n=2]) due to adverse events related to therapy. Length of stay in the hospital was also generally higher with bosutinib compared to asciminib, regardless of ward type (e.g., mean/median number of days: 10.2/6.5 versus 9.2/6.0 in general wards, 19.0/19.0 versus 13.0/5.0 in intensive care units, and 12.0/12.0 versus 7.3/3.0 in other care units). Conclusions: These results suggest that HCRU may be lower for CML-CP patients treated with asciminib compared with bosutinib.