Arnon Kater, MD, PhD, Professor of Internal Medicine at the University of Amsterdam discusses new data from the GLOW study of ibrutinib plus venetoclax (I+V) in elderly or unfit chronic lymphocytic leukemia (CLL) patients. The data were recently presented at The American Society of Hematology Meeting & Exposition (ASH 2021).

CLL is a rare blood cancer resulting in a build-up of lymphocytes in bone marrow, lymph nodes, and blood. The disease is considered treatable, but relapse is very common. Furthermore, many CLL patients cannot withstand the intensive chemotherapy needed to bring them into complete remission.

As Dr. Kater explains, the GLOW study (NCT03462719) is a phase 3 clinical trial evaluating the efficacy and safety of I+V in elderly or unfit CLL patients. In this trial, patients receiving I+V are compared to patients receiving chlorambucil plus obinutuzumab (C+O). The primary endpoint is progression-free survival and that data was presented earlier this year. Overall, it was found that risk of disease progression or death was reduced by approximately 78% in patients receiving I+V compared to those receiving C+O. 

At ASH 2021, new data was presented looking at undetectable minimal residual disease (uMRD), which is an established predictive marker for PFS in CLL following chemoimmunotherapy. The new data demonstrate that the average rate of uMRD was significantly higher for I+V vs C+O in bone marrow (51.9% vs 17.1%) and in peripheral blood (54.7% vs 39.0%). Furthermore, sustainability of uMRD response between 3 and 12 months following end of treatment was measured; 80.4% of patients in the I+V cohort had sustained uMRD below 10-5 vs. 26.3%  in the C+O cohort.

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