Relapsed CLL: ofatumumab maintenance significantly improves PFS vs observation

  • van Oers M & al.
  • Blood Cancer J
  • 4 Dec 2019

  • curated by David Reilly
  • Univadis Clinical Summaries
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Takeaway

  • In final analysis of the PROLONG study in patients with relapsed chronic lymphocytic leukemia (CLL), maintenance ofatumumab delivered a significant improvement in PFS and extended time to next treatment (TTNT) vs observation.

Why this matters

  • As CLL remains generally incurable, PFS and OS remain the most important endpoints in its treatment.

Study design

  • Final analysis of the phase 3 PROLONG study to investigate ofatumumab maintenance (n=240) vs observation (n=240) in 480 patients with relapsed CLL who achieved partial (PR) or complete remission (CR) with second-line or third-line treatment.
  • Funding: GlaxoSmithKline; Novartis.

Key results

  • Median investigator-assessed PFS with ofatumumab, 34.2 (95% CI, 29.7-38.0) months vs 16.9 (95% CI, 13.0-20.4) months with observation.
    • HR for PFS, 0.55 (95% CI, 0.43-0.70; P<.0001>
  • The PFS benefit with ofatumumab was seen across most patient subgroups with the exception of those with 17p deletion at relapse on study.
  • TTNT with ofatumumab, 37.4 (95% CI, 30.6-42.6) months vs 27.6 (95% CI, 23.5-32.6) months with observation.
  • Median OS was not reached in either study group: HR, 0.99 (95% CI, 0.72-1.37).
  • 44% experienced grade ≥3 adverse events with ofatumumab vs 31% with observation.

Limitations

  • Limited cytogenetic data.