Comparative Effectiveness of Asciminib vs Bosutinib for CML in Chronic Phase

A quarter of adults with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase previously treated with two or more tyrosine kinase inhibitors (TKIs) achieved major molecular response by week 24 with asciminib, compared with 13% with bosutinib, according to findings published in Blood.

The multicenter, open-label study randomized 233 patients 2:1 to asciminib 40 mg two times a day or bosutinib 500 mg once a day. The primary end point of the study was the rate of major molecular response at 24 weeks.

At week 24, the study showed the rate of major molecular response was 12% higher with asciminib compared with bosutinib. Meanwhile, the complete cytogenetic response rate was 41% in patients receiving asciminib and 24% in patients receiving bosutinib, a difference of 17%.

Patients continued treatment until they experienced unacceptable toxicity or treatment failure. The study demonstrated a median treatment duration of 67 weeks with asciminib and 30 weeks with bosutinib.

“The results favored asciminib in patients with lack of efficacy on their prior TKI, and the benefit was less pronounced in patients with intolerance,” authors concluded. “Moreover, the benefit of asciminib over bosutinib was confirmed even after adjusting for relevant prognostic variables that were not balanced between treatment arms, such as number of prior lines of TKI therapy and reason for discontinuation of the last TKI.”

Reference:
Réa D, Mauro MJ, Boquimpani C, et al. A phase 3, open-label, randomized study of asciminib, a STAMP inhibitor, vs bosutinib in CML after 2 or more prior TKIs. Blood. 2021;138(21):2031-2041. doi:10.1182/blood.2020009984