(ChemotherapyAdvisor) – Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus lapatinib is a “feasible” treatment for women diagnosed with human epidermal growth factor receptor 2 (HER2) overexpressing metastatic breast cancer who have received no more than one prior chemotherapy regimen, according to a phase 2 open-label, single-arm multicenter clinical study (NCT00709761) published in Breast Cancer Research and Treatment.

“Lapatinib 1,000 mg with nab-paclitaxel 100 mg/m2 IV is feasible with manageable and predictable toxicity and an ORR (overall response rate) of 53%, comparing favorably with other HER2-based combinations in this setting,” reported lead author D.A. Yardley, MD, of the Sarah Cannon Research Institute in Nashville, TN, and coauthors.

Lapatinib is an oral, reversible inhibitor of epidermal growth factor receptor and HER2 tyrosine kinase. The authors enrolled 60 patients age 18 years or older with histologically confirmed HER2+ stage IV breast cancer. The first five patients enrolled in the study developed grade 3 neutropenia and neutropenic fever with diarrhea at initially-planned study doses, leading to a dose reduction for both nab-paclitaxel and lapatinib. Subsequent patients (n=55) received nab-paclitaxel (100 mg/m2 IV on days 1, 8 and 15, every 28 days) and lapatinib 1,000 mg orally once daily, the authors reported.

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Investigator-assessed ORR was 53% (n=32; 95% CI: 40.7-66.0), “with the majority of patient responses demonstrating a PR (partial response; 47%),” they found. “Four (7%) patient responses demonstrated a CR (complete response), and ten (17%) a stable disease,” they added.

Some of the coauthors are employees of GlaxoSmithKline or Celgene, and own stock in those companies, the authors disclosed.