Adding Trastuzumab to Chemotherapy Improves OS, Review Concludes

A recent study sought to investigate the overall survival (OS) advantage of the addition of trastuzumab to chemotherapy for patients with human epidermal growth factor 2- (HER2-) positive early breast cancer (EBC).

The researchers conducted a systematic literature review to identify randomized controlled trials and non-randomized studies that were published from January 1, 1990, to January 19, 2017. The review compared systemic therapies used in the neoadjuvant and adjuvant settings for the treatment of patients with HER2-positive EBC.

In total, the review identified 31 unique studies (28 randomized controlled trials and 3 non-randomized studies) that were included in the overall survival analyses. The included studies took place from 2008 to 2016. Cumulative network meta-analyses (cNMAs) of OS were conducted to assess the published literature over time. Using the cNMA approach allowed for a simultaneous comparison of multiple treatments that may not have been directly compared in the same study.

In total, 7341 patients (380 deaths) were included in the 2008 evidence network. By 2016, the number of patients included grew to 33,029 (3929 deaths). Based on the results from the reference case, cNMA, evidence in 2008 demonstrated an OS advantage for trastuzumab and chemotherapy compared with chemotherapy alone (hazard ratio [HR], 0.66; 95% CI, 0.03-12.27). The data showed that survival benefit strengthened over time, with an overall survival benefit in 2016 of HR 0.70 (95% CI, 0.62-0.82).

Overall, the researchers found that initial evidence in the reference case (randomized controlled trials alone) demonstrated that there was an OS advantage for trastuzumab/chemotherapy compared with chemotherapy monotherapy.

However, as additional OS data were published, the precision around the survival benefit became more notable over time. The researchers found that trastuzumab/anthracycline-containing chemotherapy and trastuzumab/non-anthracycline-containing chemotherapy provided similar OS advantages for patients with HER2-positive early breast cancer.

The study’s authors noted that these findings underscore why trastuzumab plus chemotherapy is the established standard of care in HER2-positive early breast cancer. Furthermore, the researchers found that the benefits of early patient access “far outweighed the risk of waiting for more precise information.”

Reference

Wilson F, Coombes M, Brezden-Masley C, et al. Herceptin (trastuzumab) in HER2-positive early breast cancer: a systematic review and cumulative network meta-analysis [published online November 14, 2018]. BMC. https://doi.org/10.1186/s13643-018-0854-y?rel=0" .