For older patients with untreated chronic lymphocytic leukemia (CLL), treatment with ibrutinib alone or in combination with rituximab is associated with improved progression-free survival versus bendamustine plus rituximab, according to a study published online Dec. 1 in the New England Journal of Medicine. The research was published to coincide with the annual meeting of the American Society of Hematology, held from Dec. 1 to 4 in San Diego.
Jennifer A. Woyach, M.D., from The Ohio State University Comprehensive Cancer Center in Columbus, and colleagues randomly assigned patients aged 65 years or older with untreated CLL to receive bendamustine plus rituximab (183 patients), ibrutinib (182 patients), or ibrutinib plus rituximab (182 patients). Patients were followed for a primary end point of progression-free survival.
The researchers found that only the bendamustine-plus-rituximab group reached the median progression-free survival. The estimated percentage of patients with progression-free survival at two years was 74, 87, and 88 percent for bendamustine plus rituximab, ibrutinib alone (hazard ratio for progression or death, 0.39), and ibrutinib plus rituximab (hazard ratio, 0.38). With regard to progression-free survival, there was no significant difference between the ibrutinib-plus-rituximab group and the ibrutinib group. No significant difference was seen between the groups for overall survival with a median follow-up of 38 months.
"The results of this analysis show the efficacy of treatment with continuous ibrutinib among patients with untreated CLL, but the results also raise the issue of whether indefinite therapy with a BTK inhibitor is needed," the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including Pharmacyclics, which manufactures ibrutinib and partially funded the study.