Although survival rates were similar, patients with chronic lymphocytic leukemia treated with Calquence experienced fewer side effects than those who received Imbruvica.
Treatment with Calquence (acalabrutinib) induced similar survival results to Imbruvica (ibrutinib) and was considered noninferior in previously treated patients with chronic lymphocytic leukemia (CLL) with deletion 17p or deletion 11q, according to results of a phase 3 trial.
However, the data, which were presented during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, indicated that the use of Calquence was associated with a more tolerable safety profile than Imbruvica.
“Acalabrutinib is a more selective inhibitor of (Bruton tyrosine kinase [BTK]) and has been known to have less (side effects) when compared across trials. [Until] today, no clinical trial has directly compared (Imbruvica) to (Calquence) in previously treated CLL. Our trial presented here does this,” said lead study author Dr. John C. Byrd, a professor of hematology at The Ohio State University Comprehensive Cancer Center, in a presentation of the findings.
Byrd and colleagues randomized 533 patients (median age, 66 years) to receive the BTK inhibitor Calquence or Imbruvica until disease progression or unacceptable toxicity. Assessing progression-free survival (time during and after treatment when the patient lives without disease progression) served as the main goal of the study. Other goals included evaluating any instances of atrial fibrillation (irregular and often heartbeat, as well as instances of serious or severe infection and measuring overall survival (time that a patient with cancer is still alive).
Overall, 268 patients received Calquence and 265 received Imbruvica. On average, patients had received two prior lines of therapies; 45.2% of patients had deletion 17p and 64.2% had deletion 11q.
At a median follow-up of 40.9 months, Calquence was noninferior to Imbruvica, with a progression-free survival of 38.4 months in both groups.
However, Calquence was associated with fewer occurrences of atrial fibrillation compared to Imbruvica (9.4% versus 16.0%, respectively).
“When considering de-novo atrial fibrillation flutter occurring in patients who had never had this before, the difference between (Imbruvica) and (Calquence) was greater,” Byrd explained.
Other outcomes were comparable between the two treatments: 30.8% of patients on Calquence and 30% of patients on Imbruvica experienced serious or severe infection.
Average overall survival was not reached in either treatment group. There were 63 (23.5%) deaths in the Calquence group and 73 (27.5%) in the Imbruvica group.
Moreover, patients in the Calquence treatment group had a lower instance of hypertension than Imbruvica (9.4% vs. 23.2%, respectively), as well as joint pain (15.8% vs 22.8%) and diarrhea (34.3% vs 46.0%). Calquence, however, was associated with a higher incidence of headache (34.6% vs 20.2%, respectively) and cough (28.9% vs 21.3%) than Imbruvica.
“Despite a similar (independent review committee) progression-free survival, survival non-statistically favored (Calquence) with 10 fewer deaths,” Byrd concluded. “These results demonstrate that (Calquence) is better tolerated and safer than (Imbruvica and has) similar efficacy in previously treated patients with CLL.”
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