Calquence (acalabrutinib), a treatment for mantle cell lymphoma (MCL) patients who have failed at least one prior therapy, reduced tumor burden in four of five patients in a Phase 2 clinical trial, with responses lasting a median 26 months, AstraZeneca and Acerta Pharma reported.
The findings were presented at the recent American Society of Hematology (ASH) 2018 Meeting, in San Diego, in a poster titled “Long-Term Follow-up of Acalabrutinib Monotherapy in Patients with Relapsed/Refractory Mantle Cell Lymphoma.”
Calquence is a highly selective and potent inhibitor of Bruton tyrosine kinase, a B-cell protein whose activity is abnormally increased in certain types of non-Hodgkin’s lymphoma, including MCL.
In October 2017, the treatment received accelerated approval in the U.S. for MCL patients given at least one prior line of therapy, after promising response rates seen in the ACE-LY-004 Phase 2 trial (NCT02213926).
The trial included 124 patients, median age 64 years, who had received one to five prior treatments for their condition. Participants were given Calquence 100 mg twice daily until their disease worsened or they experienced signs of severe toxicity.
Initial data, collected after a median follow-up of 15.2 months, showed that 81% of patients responded to Calquence — 40% who had complete responses — and 9% of patients had their disease stabilized, amounting to a total disease control rate of 90%.
Now, researchers reported updated data from ACE-LY-004, after patients were followed for a median of two years and two months.
Response rates closely matched those reported previously, with 81% of patients responding to the treatment, including 43% who had complete responses and 38% partial responses. Responses lasted a median of 26 months, and 40% of patients were still receiving treatment with Calquence at the time of the analysis.
Patients lived 20 months without seeing their disease worsening, researchers reported. Also, while more than half of patients remained alive at the time of data cutoff, researchers estimate that the median overall survival at two years was 72%.
The most common adverse events were headache, diarrhea, fatigue, cough, and muscle pain, which were mostly mild to moderate in severity. Severe or life-threatening adverse events included anemia, low levels of neutrophils, and pneumonia. Ten patients discontinued treatment and six died of adverse reactions, but none of the fatalities was considered related to treatment.
“Response to acalabrutinib remained consistent during long-term (>24-month) follow-up, including high response rates, median PFS of  months, and a median [overall survival] that has not yet been reached, confirming efficacy in patients with relapsed/refractory MCL,” researchers concluded. “The [adverse events] profile was largely similar to earlier reporting, with limited additional safety events observed with an additional year of follow-up.”
“It’s encouraging to see the sustained duration of response in the updated analysis and the safety profile of acalabrutinib maintained consistently over time in MCL patients,” Michael L. Wang, MD, principal investigator of the ACE-LY-004 MCL trial, said in a press release.
“As we gain more and more experience with this therapy, its importance as a treatment option for relapsed or refractory MCL is being more fully realized across the clinical and patient community,” said Wang, a professor in the department of lymphoma/myeloma at the University of Texas MD Anderson Cancer Center.