Trastuzumab combined with doublet or single-agent chemotherapy as first-line therapy for HER2-positive metastatic breast cancer

Abstract

Purpose

To investigate the efficacy and safety of doublet versus single-agent chemotherapy (CT) plus trastuzumab (H) as first-line therapy for human epidermal growth factor 2 receptor (HER2)-positive metastatic breast cancer (MBC).

Methods

We searched for randomized clinical trials (RCTs) that evaluated the treatment effects of single-agent or doublet CT+H as first-line therapies for HER2-positive MBC. The main outcomes measured for this study included the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). A meta-analysis and trial sequential analysis (TSA) were performed, and the study quality was evaluated using the GRADE framework. The PROSPERO registry number of our analysis is CRD42016043766.

Results

The results from four RCTs including 1044 participants were pooled. Moderate-quality evidence indicated that compared with single-agent CT+H, doublet CT+H correlated better with prolonged PFS (hazard ratio [HR] 0.69, 95% confidence interval [CI] 0.63–0.75, P < 0.0001) and OS (HR = 0.90, 95% CI 0.88–0.92, P < 0.0001). However, moderate-quality evidence revealed no significant difference between the two regimens regarding the ORR (relative risk [RR] = 1.07, 95% CI 0.98–1.17, P = 0.157), which was confirmed by TSA, indicating that the cumulative Z-curve entered the futility area. Moderate-quality evidence indicated that treatment-related grade 3 or 4 toxicities of thrombocytopenia (RR = 4.08, P = 0.000), nausea/vomiting (RR = 4.26, P = 0.002), diarrhea (RR = 2.81, P = 0.002), and stomatitis (RR = 5.02, P = 0.003) were observed more frequently with doublet CT+H than with single-agent CT+H.

Conclusions

Compared with single-agent CT, the combination of doublet CT with trastuzumab as first-line therapy for HER2-positive MBC is associated with longer PFS and OS, but more treatment-related grade 3 or 4 toxicities. Therefore, doublet CT appears to be an appropriate regimen for HER2-positive MBC with a good performance status.

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