A new scheme for the treatment of HER2 positive advanced breast cancer

What is it about?

This study aimed to observe the efficacy and safety of inetetamab and pyrotinib in combination with vinorelbine in second-line therapy and beyond in HER2-positive metastatic breast cancer (MBC). 52 patients were included; 13 patients received 2nd-line treatment and 39 patients received ≥3rd-line treatment. The median PFS (mPFS) for all patients treated with inetetamab + pyrotinib + vinorelbine was 7 months. The mPFS of the 2nd-line subgroup was significantly better than that of the ≥3rd-line subgroup (17 vs. 5 months, P = 0.001). The mPFS of the subgroups that received trastuzumab (H) or trastuzumab and pertuzumab (HP) only was significantly better than that of the H or HP and tyrosine kinase inhibitor (TKI) subgroups (8 vs. 5 months, P = 0.030). The mPFS of the HER2 resistance subgroup was better than that of the HER2 refractoriness subgroup (14 vs. 7 months, P = 0.025). Cox regression analysis showed that the treatment line (2nd-line more so than ≥3rd-line) was an independent prognostic factor for PFS. In addition, the ORR and CBR of 2nd-line patients were significantly higher than those of ≥3rd-line patients (69.2% vs. 30.8% and 92.3% vs. 64.1%, respectively). The most common hematological toxicities were leukopenia and neutropenia, and the most common nonhematological toxicity was diarrhea.

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Photo by Tim Mossholder on Unsplash

Photo by Tim Mossholder on Unsplash

Why is it important?

For HER2-positive metastatic breast cancer patients who cannot use antibody‒drug conjugates (ADCs) as a standard second-line therapy due to cost‒benefit ratios and those who receive third-line therapy and beyond, with no preferred regimens according to the National Comprehensive Cancer Network (NCCN) guidelines, it is necessary to explore new anti-HER2-targeted therapies to meet their clinical needs. Here, we provide evidence to support the efficacy and safety of inetetamab and pyrotinib combined with vinorelbine in a real-world setting. The median progression-free survival (mPFS) for all patients treated with inetetamab + pyrotinib + vinorelbine was 7 months. The mPFS of the 2nd-line subgroup was significantly better than that of the ≥3rd-line subgroup (17 vs. 5 months, P = 0.001). The ORR and CBR of 2nd-line patients were significantly higher than those of ≥3rd-line patients (69.2% vs. 30.8% and 92.3% vs. 64.1%, respectively). The most common adverse events were leukopenia, neutropenia and diarrhea, which were mostly Grade 1-2, and no patients discontinued medication due to adverse reactions.

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