A clinical practice comparison of patients with chronic lymphocytic leukemia with and without deletion 17p receiving first-line treatment with ibrutinib

Among patients with chronic lymphocytic leukemia (CLL) with deletion 17p (del[17p]), evidence from clinical trials for the effectiveness of single-agent ibrutinib as first-line (1L) therapy is limited. This retrospective analysis compared real-world clinical outcomes among patients with CLL, with and without del(17p), treated with 1L ibrutinib monotherapy. Overall survival (OS), time-to-next-treatment (TTNT), time-to-treatmentdiscontinuation (TTD), and reasons for ibrutinib discontinuation were evaluated. Using data from a real-world database, patients included were aged .18 years, had been diagnosed with CLL between 1/1/2011 and 12/31/2019, had received cytogenetic testing, and had received 1L ibrutinib monotherapy. A total of 1,069 patients were included in the analysis (62.7% male; median age 69 years); 23.8% (n=254) had del(17p). Median OS was significantly shorter in del(17p)-present patients than in patients without (57.7 months vs. median not reached; P=0.0006). Similar results were observed for median TTNT (49.4 months vs. median not reached, P=0.0330). Median TTD was non-significantly shorter in the del(17p)-present group (32.5 months vs. 42.9 months, P=0.3370). Adjusted Cox proportional hazards model results showed that the del(17p)-present group was at significantly higher risk of death than the del(17p)-absent group (HR 1.70, P=0.0031). Event rates for switching to new treatment and discontinuation were higher but not statistically significant. The most common reason for ibrutinib discontinuation in both groups was toxicity, but discontinuation due to progression was significantly higher among del(17p)-present patients (20% vs. 6%; P