Dr. Ryan on Objectives for Investigating Ibrutinib Plus Obinutuzumab in R/R CLL

Christine Ryan, MD, hematology/oncology fellow, the Department of Medical Oncology, the Dana-Farber Cancer Institute, discusses the objectives for investigating different sequencing options for ibrutinib (Imbruvica) plus obinutuzumab (Gazyva) in relapsed/refractory chronic lymphocytic leukemia (CLL).

A phase 1b trial (NCT02537613) evaluated different sequencing options for the combination of ibrutinib and obinutuzumab in patients with relapsed/refractory CLL who received at least 1 prior line of CLL-directed therapy.

Safety among patients across all sequencing regimens served as the trial’s primary end point, and secondary end points included overall response rate at 6 and 24 months, plus duration of response and progression-free survival at 24 months, Ryan explains. The rate of undetectable minimal residual disease in the peripheral blood and bone marrow at 6 months was also a key secondary end point, Ryan adds.

Patients were randomized to receive obinutuzumab followed by ibrutinib in arm A, ibrutinib followed by obinutuzumab in arm B, or obinutuzumab plus ibrutinib concurrently in arm C, and dosing mirrored current standard-of-care regimens, Ryan continues. Once patients in all arms started on ibrutinib, the agent was administered daily until disease progression or unacceptable toxicity, Ryan concludes.