How Does Acalabrutinib Measure Up Against Ibrutinib in CLL in Phase III Trial?
Posted: Thursday, August 12, 2021
A phase III trial conducted by Wojciech Jurczak, MD, PhD, of Maria Sklodowska-Curie National Research Institute of Oncology, Krakow, Poland, and colleagues demonstrated that treatment with acalabrutinib for patients with previously treated chronic lymphocytic leukemia (CLL) yielded similar progression-free survival as did ibrutinib, but with fewer cardiovascular adverse events. This is reportedly the first study comparing these Bruton’s tyrosine kinase inhibitors, and the trial results were published in the Journal of Clinical Oncology.
This open-label trial focused on 533 patients with previously treated CLL who had the presence of del(17)(p13.1) and/or del(11)(q22.3). Participants were randomly assigned to receive either 420 mg of ibrutinib once daily or 100 mg twice daily of acalabrutinib.
A total of 268 and 265 individuals were stratified into the acalabrutinib and ibrutinib cohorts, respectively. The median follow-up was 40.9 months, with an objective response rate of 77% for those given ibrutinib and 81% for individuals treated with acalabrutinib. At the time of data cutoff, 109 patients given ibrutinib and 124 patients treated with acalabrutinib remained on treatment. Although the overall survival was not reached, the progression-free survival for both cohorts was 38.4 months, the authors reported, deeming acalabrutinib noninferior to ibrutinib.
A significantly lower rate of atrial fibrillation or atrial flutter was observed in patients treated with acalabrutinib (9.4%) than those given ibrutinib (16%). The most common adverse events were urinary tract infection, arthralgia, diarrhea, hypertension, back pain, contusion, muscle spasms, and headache—also occurring less often in participants treated with acalabrutinib. Grade 3 or higher infections and Richter’s transformation were observed at similar rates in both groups, but 73 and 63 deaths occurred with ibrutinib and acalabrutinib, respectively. Notably, 21.3% of individuals treated with ibrutinib discontinued treatment due to adverse events, whereas 14.7% of those given acalabrutinib discontinued therapy.
Disclosure: For full disclosures of the study authors, visit ascopubs.org.
