Outcomes of First-Line Ibrutinib in Patients with Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) and High-Risk Genomic Features with up to 6.5 Years Follow-up: Integrated Analysis of Two Phase 3 Studies (RESONATE-2 and iLLUMINATE)

Background Genomic abnormalities such as del(17p)/TP53 mutation, del(11q), and unmutated IGHV are risk factors that predict inferior outcomes with chemoimmunotherapy (CIT) in patients (pts) with CLL/SLL (Byrd J Clin Oncol 2006). Mutations in BIRC3, NOTCH1, SF3B1, and XPO1 have also been associated with poor outcomes with CIT in pts with CLL (Foa Haematologica 2013; Jain Am J Hematol 2016). Ibrutinib (ibr) is the only once-daily Bruton's tyrosine kinase inhibitor with significant progression-free survival (PFS) and overall survival (OS) benefit shown in multiple randomized phase 3 studies versus established therapies in pts with previously untreated or relapsed/refractory CLL/SLL. Superior outcomes were demonstrated with ibr-based therapy versus comparators in the overall population, and in pts with high-risk disease features, such as TP53 aberrations, del(11q), and/or unmutated IGHV in the RESONATE-2 study of first-line single-agent ibr (Burger Leukemia 2020) and in the iLLUMINATE study of first-line ibr-obinutuzumab (Moreno Lancet Oncol 2019). In pts with relapsed/refractory CLL/SLL who were treated with ibr, mutations in BIRC3, NOTCH1, SF3B1, or XPO1 had no significant impact on the PFS benefit conferred by ibr (Byrd Blood 2019). To better understand outcomes in pts with previously untreated CLL with various high-risk genomic features, including integrated FISH cytogenetics and single gene mutations, we performed a pooled analysis of two phase 3 studies of ibr-based therapy in the first-line treatment of CLL/SLL (RESONATE-2 and iLLUMINATE). Methods In RESONATE-2 (NCT01722487), pts aged ≥65 years without del(17p) were randomized to single-agent ibr or chlorambucil (clb). In iLLUMINATE (NCT02264574), pts aged ≥65 years, or