Calquence Tends to Be a Shorter-Lived Frontline Regimen Than Imbruvica for Leukemia Subtype

Treatment duration with frontline Calquence (acalabrutinib) tended to be shorter than Imbruvica (ibrutinib) for patients with chronic lymphocytic leukemia, meaning that patients on the former regimen tended to move on to the next treatment or intensify their Calquence regimen quicker than those given Imbruvica, according to findings from a real-world study.

Real-world studies utilize patient data, such as that found on electronic medical records, of patients who are being treated outside of a clinical trial setting. These real-world data can lend insight into two drugs that are not being compared directly in a head-to-head clinical trial.

“We are unlikely to get a prospective comparison of (Imbruvica) and (Calquence) in the frontline setting,” said study author Dr. Ryan Jacobs, hematologist-oncologist at Atrium Health Levine Cancer Institute in Charlotte, North Carolina, in a presentation of the data at the 2022 American Society of Hematology Annual Meeting. “With that in mind, we (utilized) our real-world data and leveraging it to look at what we would deem as a real-world marker of (progression-free survival), which is time to next treatment, and look and see if there were any differences between these two groups.”

The researchers analyzed data from patients with chronic lymphocytic leukemia undergoing frontline treatment for their disease — 710 with Imbruvica and 373 with Calquence — between Nov. 21, 2019 (the day the Food and Drug Administration approved Calquence for chronic lymphocytic leukemia) and April 30, 2022.

Most patient characteristics were balanced between the two groups; average age was 71.5 and 72.4 years in the Imbruvica and Calquence arms, respectively; 38.5% and 38.3% were women; comorbidity profiles were also similar between the two groups.

The Imbruvica arm had a higher percentage of patients with chronic pulmonary disease (13.2% versus 8.6%), peripheral vascular disease (7.6% versus 4%) and high blood pressure (41.4% versus 32.2%). Baseline corticosteroids use was lower in the Imbruvica group (14.5%) than in the Calquence group (20.1%), as was antiplatelet use (7% versus 3.5%).

A total of 7.5% of patients in the Calquence arm initiated next or additional treatment, compared to 5.9% in the Imbruvica arm, making those on Calquence 89% more likely to start additional therapy.

The average time to next treatment was 6.8 months in the Imbruvica group and 4.6 months in the Calquence arm. Of note, in both groups, the most common next treatment was Venclexta (venetoclax).

Jacobs emphasized that time to next treatment could be a “meaningful measure” of disease — particularly when it comes to progression-free survival, which is the time a patient survives without their disease getting worse.

“Unfortunately, prospective trials don't always report time to next treatment, but for indolent lymphomas like chronic lymphocytic leukemia and follicular lymphoma, for example, where we might have disease progression that doesn't meet clinical progression and doesn't actually immediately lead to initiation of therapy, time to next treatment could be considered a potentially even more meaningful clinical endpoint for the (chronic lymphocytic leukemia) patient. And we feel like it's a good metric to look at with our real-world data,” he said.

Further research in this space is warranted, Jacobs said, noting that he’d be interested in seeing longer follow-up and a larger sample size (especially looking at those treated with first-line Calquence) comparing these two drugs, which are BTK inhibitors.

“Of course, this data generates a lot of questions. We have questions too, (such as) what might have potentially lead to these differences that we observed,” he said.

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