Clinicians ought to counsel patients with chronic lymphocytic leukemia (CLL) about weight gain when treating them with the oral Bruton tyrosine kinase inhibitor ibrutinib, according to results from an observational study published in the American Journal of Hematology.

Researchers examined medical records of 118 patients with CLL treated with ibrutinib for at least 6 months between November 2011 and June 2018. The researchers collected data on height, weight, and body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) 1 year prior to ibrutinib initiation. Patients were subsequently measured at treatment initiation and at 1, 2, 3, 6, and 12 months after initiation.

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The researchers assessed weight change at 1 year after initiation of ibrutinib therapy as the primary outcome. The cohort was 61% male, and median age was 67 years (range, 47-88) at initiation. Among the patients, 44 were treatment-naive. All patients responded to treatment at 6 months after ibrutinib initiation, and 77 patients remained on ibrutinib at the study’s completion, after a median follow-up of 22.6 months (range, 6-77).

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At the start of treatment, median patient weight was 81 kg (range, 44-125) and median BMI was 27 (range, 17-42). There were 2 patients who were underweight, 32 who were normal weight, 57 who were overweight, and 27 who were obese. Patients experienced an average weight gain of 1.8 kg (P <.001) and 2.4 kg (P <.001) at 6 and 12 months, respectively, after ibrutinib initiation.

Average weight gain did not reach significance until 3 months after initiation of therapy. Weight gain was sustained past 1 year, reaching 3.8 kg at 2 years after initiation before plateauing (P <.001).

These findings are similar to those reported for other Bruton tyrosine kinase inhibitors, including acalabrutinib, according to the researchers. They recommended that patients starting therapy with ibrutinib should be thoroughly counseled regarding healthy lifestyle goals, including weight management. “Active monitoring of [patients’] weight should be incorporated into their care, and appropriate referrals should be made once patients appear to be gaining any weight,” wrote the researchers.


1.     Williams AM, Baran AM, Schaffer M, et al. Significant weight gain in CLL patients treated with ibrutinib: a potentially deleterious consequence of therapy [published online October 17, 2019]. Am J Hematol. doi:10.1002/ajh.25663