The following article features coverage from the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting. Click here to read more of Hematology Advisor‘s conference coverage.

Compared with ibrutinib, acalabrutinib may lower the rate of treatment-related adverse events (AEs) while maintaining a similar progression-free survival (PFS) rate among patients with previously treated chronic lymphocytic leukemia (CLL), according to research presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.

Bruton kinase inhibitors, including ibrutinib, have improved outcomes among patients with hematological diseases, including CLL. Acalabrutinib, an inhibitor of Bruton kinase that has increased selectivity in comparison with ibrutinib, may help to improve treatment tolerability. For this randomized phase 3 trial (ClinicalTrials.gov Identifier: NCT02477696), researchers evaluated the safety and efficacy of acalabrutinib vs ibrutinib among previously treated patients with CLL.

Overall, 533 patients were enrolled and randomly assigned to receive acalabrutinib (268 patients) or ibrutinib (265 patients). All patients had del(17p) or del(11q) disease and were stratified by performance status and number of prior therapies. The median patient age was 66 years, the median number of prior therapy lines was 2, a total of 45.2% of patients had del(17p) disease, and 64.2% of patients had del(11q) disease.


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The median follow-up was 40.9 months (range, 0-59.1). PFS was not significantly different between the 2 groups (median, 38.4 months in both groups; hazard ratio, 1.00), and the median overall survival was not reached in either arm. Acalabrutinib was, however, linked with fewer cases of atrial fibrillation (9.4% vs 16%; P =.023).

Instances of other AEs, including grade 3 or worse infection (30.8% in the acalabrutinib group vs 30% in the ibrutinib group) and Richter transformation (3.8% vs 4.9%, respectively), were similar between the 2 groups.

While hypertension (9.4% in the acalabrutinib group vs 23.2% in the ibrutinib group), arthralgia (15.8% vs 22.8%, respectively), and diarrhea (34.6% vs 46.0%, respectively) were more common in the ibrutinib group, headache (34.6% vs 20.2%, respectively) and cough (28.9% vs 21.3%, respectively) were more common in the acalabrutinib group.

Treatment discontinuation due to an AE was noted in 14.7% of patients in the acalabrutinib group vs 21.3% of patients in the ibrutinib group.

Disclosure: The study author(s) declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Read more of Hematology Advisor’s coverage of the 2021 ASCO Annual Meeting by visiting the conference page.

Reference

Byrd JC, Hillmen P, Ghia P, et al. First results of a head-to-head trial of acalabrutinib versus ibrutinib in previously treated chronic lymphocytic leukemia. J Clin Oncol. 2021;39:(suppl 15; abstr 7500). doi:10.1200/JCO.2021.39.15_suppl.7500