ESMO 2019 — Triple negative breast cancer: trilaciclib improves survival when given with gemcitabine+carboplatin

  • Jo Whelan
  • Oncology Conference reports
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  • Trilaciclib improved survival when given in addition to gemcitabine+carboplatin (GC) in metastatic triple negative breast cancer, in this interim analysis of a phase 2 trial.
  • A phase 3 study is planned to explore this encouraging finding.
  • Trilaciclib may enhance CD8+ T cell activation.

Why this matters

  • There is a high unmet need for effective treatments for triple-negative breast cancer.
  • GC causes cumulative myelosuppression, which may be treatment-limiting. It was hypothesised that adding trilaciclib (an intravenous CDK 4/6 inhibitor) might decrease myelotoxicity and improve anti-tumour efficacy.

Key results

  • Median overall survival in the pooled trilaciclib+GC groups was 20.1 months (95% CI 15.3, NE), compared with 12.6 (6.3, 15.6) with GC alone, HR 0.36 (0.19, 0.67).
  • There was no significant difference in PFS or response rate between the treatments.
  • Addition of trilaciclib did not reduce myelosuppression, but patients in the trilaciclib groups were able to receive twice as many cycles of treatment as those receiving GC alone.
  • Despite increased exposure to GC, there was no increase in high-grade toxicity and no worsening of health-related quality of life in the trilaciclib groups.

Study design

  • Patients (n=102) were randomised to GC alone on days 1 and 8 or trilaciclib+GC on 1 of 2 different schedules, given every 21 days until disease progression or unacceptable toxicity.
  • Included patients had 0-2 previous lines of cytotoxic therapy for locally recurrent or metastatic breast cancer.
  • The primary endpoint was reduction in GC-related neutropenia. PFS and OS were secondary endpoints.
  • Funding: G1 Therapeutics, Inc.


  • This was a phase 2 study with a relatively small number of patients.