HER2+ breast cancer: no help from lapatinib + vinorelbine after lapatinib, trastuzumab progression

  • Sim SH & al.
  • Br J Cancer
  • 6 Nov 2019

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • The combination of lapatinib plus vinorelbine fails to extend PFS vs vinorelbine alone in HER2+ metastatic breast cancer (mBCa) patients who progressed on both lapatinib and trastuzumab.

Why this matters

  • This is the first trial to test the efficacy and safety of continuing lapatinib after the failure of both trastuzumab and lapatinib therapies in HER2+ mBCa.

Study design

  • Open-label multicenter, randomized phase 2 study (n=149) by the Korean Cancer Study Group (KCSG BR11-16).
  • The lapatinib+vinorelbine (LV) group (lapatinib dose of 1000 mg daily and vinorelbine dose of 20 mg/m2 on days 1 and 8 every 3 weeks) was compared with the vinorelbine-only (V) group (at a dose of 30 mg/m2 on days 1 and 8 every 3 weeks).
  • Primary outcome was PFS at 18 weeks.
  • Funding: GlaxoSmithKline; National Cancer Center Korea.

Key results

  • No difference between groups on:
    • PFS at 18 weeks (LV group, 45.9% vs V group, 38.9%; P=.402).
    • Objective response rates (19.7% vs 16.9%, respectively; P=.881).
    • Median PFS (16.0 vs 12.0 weeks, respectively; HR, 0.86; 95% CI, 0.61-1.22)
    • Median OS (15.0 vs 18.9 months, respectively; HR, 1.07; 95% CI, 0.72-1.58).
  • Toxicity profiles were tolerable and similar across groups.

Limitations

  • Open-label design.
  • Short follow-up.