An Italian scoring system worked better than 2 other risk models for predicting which patients with chronic lymphocytic leukemia (CLL) patients who were administered ibrutinib would later develop potentially life-threatening heart rhythms.

The finding, based on a retrospective study of 298 patients with CLL, may help clinicians distinguish between normal risk of atrial fibrillation (AFib) due to aging and the additive risk posed by this widely used drug. 

“The important thing is that doctors already have this information in patients’ medical records, so it doesn’t require further testing to plug in numbers and come up with a score,” said William Archibald, MD, the study’s principal investigator and a resident internist at the Mayo Clinic in Rochester, Minnesota. Those scoring highest on the Italian model had an almost 50% risk of later developing AFib, he said, which may allow doctors to start planning ahead — choosing a different therapy to manage these chronic blood cancers or even stopping ibrutinib altogether.

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Results of the study were presented at a poster session of the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois. The investigators assessed patients with CLL treated with ibrutinib at the Mayo Clinic between October 2012 and November 2018 on 3 clinical prediction models — the Framingham, Italian, and Shanafelt risk scores. During a median follow-up of 24 months, 51 patients developed emergent AFib while taking the drug.

Awareness of cardiac toxicities caused by older cancer drugs date back to the 1970s, experts say, although less is known about heart problems that can arise from newer targeted drugs, such as ibrutinib, as well as new immunotherapies.1 In recent years, scientists have stepped up research into the intersection between these 2 diseases, as many more cancer patients now survive into old age.2

“These newer agents are developing so much faster than in the past, that people are using them before all the postmarketing effects are well understood,” said Lori Minasian, MD, FACP, deputy director for the National Cancer Institute’s division of cancer prevention. In the 3 diseases for which ibrutinib is indicated — CLL, Waldenström macroglobulinemia, and mantle cell lymphoma — the median patient age is 60 years or older, she said, creating a “perfect storm” in susceptible older adults and underscoring the need for collaborative research between oncologists and cardiologists in the future.