ASCO 2019 — Extended ibrutinib therapy maintains long-term advantage in CLL


  • David Reilly
  • Oncology Conference reports
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Takeaway

  • At up to 6 years' follow-up of RESONATE in patients with relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (R/R CLL/SLL), extended ibrutinib therapy maintained survival advantages over ofatumumab with no evidence of new safety signals.

Why this matters

  • Ibrutinib reduced burden of treatment in this setting as a first-in-class Bruton’s tyrosine kinase inhibitor with once-daily oral dosing.

Study design

  • Phase 3 trial of patients randomly assigned to ibrutinib monotherapy (n=195) vs ofatumumab (n=196) in patients with relapsed/refractory CLL/SLL.
  • Patients received ibrutinib until progressive disease or unacceptable toxicity; ofatumumab was given for 24 weeks.
  • Median follow-up was 64 months (range, 0.3-72 months). 
  • Funding: PharmaCyclics, LLC, an AbbVie company.

Key results

  • 68% of patients in the ofatumumab group crossed over to ibrutinib.
  • Median duration of ibrutinib therapy was 41 months (>4 years, 41%).
  • 88% objective response rate (ORR) with ibrutinib with 11% complete response (CR)/CR with incomplete bone recovery (Cri).
  • Median PFS: overall population:
    • 44.1 (95% CI, 38.5-56.2) months with ibrutinib vs 8.1 (95% CI, 7.8-8.3) with ofatumumab (HR, 0.148; P˂.0001).
  • Median PFS: high-risk genomic characteristics:
    • 44.1 (95% CI, 38.5-56.9) months with ibrutinib vs 8.0 (95% CI, 6.4-8.2) with ofatumumab (HR, 0.110; P˂.0001).
  • Median OS with ibrutinib was 67.7 (95% CI, 61.0-not estimable [NE]) months vs 65.1 (95% CI, 50.6-NE) with ofatumumab (unadjusted for crossover/censoring).
  • No new safety signals were observed.

Limitations

  • Open-label design.