Relapsed CLL: idelalisib benefit confirmed in phase 3 extension study

  • Sharman JP & al.
  • J Clin Oncol
  • 17 Apr 2019

  • curated by David Reilly
  • Univadis Clinical Summaries
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Takeaway

  • According to long-term follow-up data, idelalisib+rituximab improved outcomes vs rituximab alone in patients with relapsed chronic lymphocytic leukemia (CLL).

Why this matters

  • The phase 3 study was terminated early because of superiority being demonstrated in the idelalisib/rituximab group; participants were then eligible to transfer to the open-label idelalisib extension study.

Study design

  • Final results from a phase 3 study of patients with relapsed CLL ineligible for cytotoxic therapy, randomly assigned to idelalisib/rituximab (n=110) or placebo+rituximab (n=110).
  • The open-label idelalisib extension study included 161 patients: 75 from the idelalisib/rituximab group and 86 from the placebo/rituximab group.
  • Funding: Gilead Sciences.

Key results

  • Median OS: 40.6 (95% CI, 28.5-57.3) months with idelalisib/rituximab vs 34.6 (95% CI, 16.0-not reached) months with placebo/rituximab.
  • Median PFS: 20.3 (95% CI, 17.3-26.3) months with idelalisib/rituximab to idelalisib monotherapy.
  • Objective response rate: 85.5% (95% CI, 77.5%-91.5%) with idelalisib/rituximab to idelalisib monotherapy vs 68.2% (95% CI, 52.4%-81.4%) with placebo/rituximab to idelalisib therapy.
  • Incidence of grade ≥3 liver toxicities did not increase after 20 weeks of idelalisib.
  • 55.5% of grade ≥3 diarrhea cases occurred within the first 52 weeks of treatment; such incidences were generally managed with steroids with 2-week median time to symptom resolution.

Limitations

  • Limited sample size.