Fixed Duration Ibrutinib-Venetoclax, a Redefinition of the CLL Treatment Landscape

Abstract

The fixed-duration combination of ibrutinib and venetoclax (IV) has emerged as a highly effective therapeutic strategy for treating chronic lymphocytic leukemia (CLL), marking a significant shift in the treatment paradigm for this disease. Preclinical studies have demonstrated the synergistic anti-leukemic effects of the elements of this regimen and therefore provide a strong rationale for their combined use in the clinical setting. Clinical trial data of IV has demonstrated substantial improvements in progression-free survival (PFS) rates across both treatment-naïve and relapsed/refractory CLL. Notably, a considerable proportion of patients have achieved undetectable measurable residual disease (uMRD), a key marker of deep remission. However, several critical questions remain unanswered, including the optimal duration of IV and the prognostic significance of uMRD, particularly in high-risk CLL subsets. Whilst uMRD is widely considered a surrogate for deep remission, the precise correlation of this parameter with long-term survival outcomes in IV-treated patients requires further clarification. Moreover, emergent evidence suggests that a prolonged duration of IV therapy, beyond that currently employed, may enhance MRD clearance. Future research should focus on the optimization of BTKi/venetoclax fixed-duration regimens, particularly for elderly and medically unfit patients. In this context, the development of more selective BTKis that minimize adverse events whilst maintaining effective disease control will be crucial.