HER2-targeted regimens after prior trastuzumab for patients with HER2-positive unresectable, locally advanced or metastatic breast cancer: a network meta-analysis of randomized controlled trials

Background: Several human epidermal growth factor receptor 2 (HER2)-targeted regimens (anti-HER2 target agent combined chemotherapy) have been introduced for the treatment of HER2-positive locally advanced or metastatic breast cancer progressed after trastuzumab. We therefore conducted a network meta-analysis to compare and rank HER2-targeted regimens in this population after trastuzumab therapy. Methods: The electronic databases of PubMed, EmBase, Cochrane Central Register of Controlled Trials, and the websites of http://clinicaltrials.gov/ (US NIH) were systematically searched for published and unpublished randomized controlled trials (RCTs) from their inception to October, 2020. Nine treatment regimens were eligible to be included in this analysis. The primary outcomes were overall response rate (ORR), progression-free survival (PFS) and overall survival (OS), while the secondary outcomes were grade ≥3 adverse events. Results: A total of 2,104 citations were identified and 12 RCTs comprising 3,769 patients were selected for final analysis. For HER2 positive unresectable, locally advanced or metastatic patients progressed after trastuzumab therapy pyrotinib plus capecitabine ranked the highest surface under the cumulative ranking area (SUCRA) in PFS, ORR and its SUCRA in OS was higher than Trastuzumab emtansine (T-DM1). T-DM1 plus atezolizumab, pyrotinib plus capecitabine, and pertuzumab plus trastuzumab plus capecitabine had comparable SUCRA in OS (76.1% vs. 74.5% vs. 71.2%). Six of included studies reported any grade ≥3 adverse events, the prevalence of any grade ≥3 adverse events in lapatinib plus capecitabine (353/683), T-DM1 (213/558), trastuzumab plus capecitabine (130/218), pertuzumab plus trastuzumab plus capecitabine (118/228), pyrotinib plus capecitabine (220/384), T-DM1 plus atezolizumab (43/132) and capecitabine (24/94) were 51.7%, 38.2%, 59.6%, 51.8%, 57.3%, 32.6% and 25.5%, respectively. Specific adverse event characteristics related to different HER2-targeted regimens need to be well known ahead and managed during the therapy. Conclusions: The results indicated that for HER2 positive breast cancer with previous trastuzumab therapy pyrotinib plus capecitabine was probably more efficacious in PFS and ORR. T-DM1 plus atezolizumab, pyrotinib plus capecitabine and pertuzumab plus trastuzumab plus capecitabine have comparable effect on OS improvement and all of them were likely better than T-DM1. The risk of grade ≥3 adverse events for specific treatment regimens were also provided.