First‐Line Palliative HER2‐Targeted Therapy in HER2‐Positive Metastatic Breast Cancer Is Less Effective After Previous Adjuvant Trastuzumab‐Based Therapy

Conclusion.First‐line trastuzumab‐containing treatment regimens are less effective in patients with failure of adjuvant trastuzumab compared with trastuzumab‐naïve patients and might be due to trastuzumab resistance. The impact of trastuzumab resistance on the response on dual HER2 blockade with trastuzumab and pertuzumab and how resistance mechanisms can be used in the optimization of HER2‐targeted treatment lines need further investigation.Implications for Practice.Evidence on the efficacy of palliative trastuzumab‐based therapy after failure of trastuzumab in the adjuvant setting is limited because of a minority of patients treated with adjuvant trastuzumab in clinical trials. In this study, less clinical benefit of palliative trastuzumab‐based therapy was observed in patients relapsing after adjuvant trastuzumab compared with no adjuvant trastuzumab treatment. Subgroup analyses and multivariable analyses revealed that this was independent of possible confounding factors, including adjuvant taxane‐treatment. This might suggest a clinically meaningful impaired efficacy of trastuzumab after previous, in this case adjuvant, trastuzumab therapy. These results could have implications for treatment decision‐making after short progression‐free intervals on trastuzumab‐containing regimens in the palliative setting.
Source: The Oncologist - Category: Cancer & Oncology Authors: Tags: Symptom Management and Supportive Care, Breast Cancer Source Type: research