Background: Tyrosine kinase inhibitors (TKIs) are the mainstay treatment for chronic myeloid leukemia in chronic phase (CML-CP). Asciminib, an ABL/BCR::ABL1 inhibitor which binds to the myristoyl pocket, was recently approved in the US for patients with CML-CP previously treated with ≥2 TKIs or with the T315I mutation. This study described treatment patterns and real-world clinical outcomes among patients with CML-CP treated with asciminib in US clinical practice.

Methods: Electronic health record data from adult patients with CML-CP who initiated asciminib after ≥2 prior TKIs, without the T315I mutation, were obtained from the Flatiron Health database. Time-to-treatment discontinuation and molecular response (MR; time-to-BCR::ABL ≤0.1% and time-to-BCR::ABL1 ≤1%, separately) were evaluated from asciminib initiation (index date) using Kaplan-Meier analyses.

Results: Overall, 97 patients initiated asciminib (median age: 63 years, 50.5% female, 64.9% White) after either 2 (47.4%) or 3 (24.7%), or ≥4 (27.8%) prior TKIs. In total, 85.7% and 78.1% of patients remained on asciminib by 12- and 24-weeks postindex, respectively. Among patients with ≥1 MR assessment postindex, 31.3% (95% confidence interval [CI]: 21.6%, 43.9%) and 49.7% (95% CI: 38.1%, 62.6%) achieved or maintained BCR::ABL1 ≤0.1%, while 51.3% (95% CI: 40.1%, 63.6%) and 64.2% (95% CI: 52.6%, 75.6%) achieved or maintained BCR::ABL1 ≤1%, by 12- and 24-weeks, respectively.

Conclusions: Results of this real-world study describing clinical outcomes among patients with CML-CP treated with asciminib after ≥2 prior TKIs in the US demonstrated that asciminib was well-tolerated and effective. These findings were consistent with results from the ASCEMBL trial.