How Does del(17p) Affect Survival in Patients with CLL Treated with Ibrutinib?

For patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), genetic risk factors may significantly impact disease prognosis—including del(17p), which is a strong negative prognostic risk factor. Ibrutinib monotherapy has been shown to be effective in relapsed/refractory and treatment-naïve settings. However, there are limited frontline setting data from clinical trials evaluating patients with del(17p). Data that are available on patients with del(17p) state that they may have shorter progression-free survival and overall survival (OS). A study that was presented at the 62nd ASH Annual Meeting & Exposition evaluated baseline characteristics between patients treated with ibrutinib with and without del(17p) and compared OS, time-to-next-treatment (TTNT), and time-to-treatment discontinuation (TTD).

Data were collected from the Flatiron Health electronic health record-derived deidentified database on patients diagnosed with CLL/SLL with at least two encounters in the Flatiron Health network who received ibrutinib as first CLL-directed therapy on or after January 1, 2011. All patients underwent a cytogenetic test prior to treatment initiation to determine whether del(17p) was present. Adjusted analyses accounted for gender; age at index date; practice type (academic vs. community); Rai stage at diagnosis; Eastern Cooperative Oncology Group performance status score in the year of index date; status of deletion 11q, 13q, Trisomy 12; and immunoglobulin heavy chain mutation status.

Of 1,037 patients treated with first-line ibrutinib, 24% had del(17p). Median follow-up was 18 months. Nearly all patients (95%) were treated in community practices.

Patients with del(17p) tended to have a later Rai stage at diagnosis than those without del(17p); they also tended to start first-line therapy sooner after diagnosis. The del(17p) group had shorter median OS from initiation of treatment (57.54 months; P<0.001) than those without del(17p) (not reached [NR]).

The del(17p) present group also had shorter median TTNT (50.23 months vs. NR; P=0.063). For the whole cohort, TTD was 48.62 months; TTD was shorter in the del(17p) group (35.80 months vs. NR; P=0.117).

“Since ibrutinib is now a standard of care for such high-risk patients, a deeper understanding if the presence of del(17p) impacts survival outcomes in patients treated with ibrutinib in the frontline setting is needed. Based on the significant impact shown on OS, and to a lesser degree TTNT and TTD, these data confirm that del(17p) is a negative predictive factor in this setting. This reflects an ongoing unmet need among treatment-naïve [patients with] CLL/SLL with del(17p) status,” the study authors concluded.