Ibrutinib monotherapy may reduce the need for chemotherapy among some treatment-naive patients with chronic lymphocytic leukemia (CLL), according to a study published in the American Journal of Hematology.
Ibrutinib and various chemotherapy regimens are recommended in the first-line setting for CLL, but no studies have been performed comparing their efficacy.
For this cross-trial comparison, researchers evaluated results from the phase 3 RESONATE-2 study in which patients with CLL without del(17p) were treated with ibrutinib, and compared them with the results of three phase 3 studies assessing chemoimmunotherapy (CIT) in treatment-naive patients with CLL. CIT regimens that were evaluated included fludarabine plus cyclophosphamide and rituximab, bendamustine plus rituximab, obinutuzumab plus chlorambucil, rituximab plus chlorambucil, and ofatumumab plus chlorambucil.
Ibrutinib prolonged progression-free survival (PFS) among older and less-fit patients, younger and more-fit patients, and high-risk subgroups (eg, advanced disease, bulky lymph nodes) without del(17p) compared with CIT. Similar improvements in PFS were observed among patients without IGHV mutations, as well as in patients with del(11q) versus CIT.
Older and less-fit patients seemed to have an overall survival (OS) benefit with ibrutinib compared with CIT, but OS was comparable among younger, more-fit patients.
The authors concluded that “although definitive conclusions cannot be made due to inherent limitations of cross-trial comparisons, this report suggests that ibrutinib has a favorable benefit/risk profile and may potentially eliminate the need for chemotherapy in some patients. Randomized, comparative studies are needed to support these findings.”
Robak T, Burger JA, Tedeschi A, et al. Single-agent ibrutinib versus chemoimmunotherapy regimens for treatment-naïve patients with chronic lymphocytic leukemia: a cross-trial comparison of phase 3 studies [published online August 20, 2018]. Am J Hematol. doi: 10.1002/ajh.25259.