Targeted therapy for targeted patients: trastuzumab in adjuvant treatment of non-small-cell lung cancer

Risk of Congestive Heart Failure in Early Breast Cancer Patients Undergoing Adjuvant Treatment With Trastuzumab: A Meta-Analysis

BACKGROUND

The use of trastuzumab has proven to be a successful strategy in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer; however, it is associated with an increased risk of cardiac dysfunction. We performed an up-to-date, comprehensive meta-analysis to clarify the risk of congestive heart failure (CHF) in patients with early breast cancer receiving different durations of adjuvant trastuzumab with the longest-term follow-up.

METHODS

Eligible studies included randomized control trials of HER2-positive early breast cancer patients with or without trastuzumab in adjuvant chemotherapy. Adequate reporting of CHF data were required for inclusion. Statistical analyses were conducted to calculate the overall incidence, relative risk (RR), and 95% confidence interval (CI) by use of a fixed-effects model.

RESULTS

Six randomized control trials including 18,111 patients were identified. The overall incidence of high-grade CHF in patients treated with trastuzumab versus placebo was 1.44% (95% CI, 0.79%-2.64%) and the RR was 3.19 (95% CI, 2.03-5.02; p < .00001). In subgroup analysis, the difference in CHF incidence failed to achieve significance. The RR for 8 mg/kg trastuzumab (high dose) was greater than that for 4 mg/kg (low dose) (RR, 6.79, 95% CI, 2.03-22.72, p = .0001; versus RR, 2.64; 95% CI, 1.61-4.32; p = .002). Additionally, higher RRs were observed for patients receiving trastuzumab for 1 year (RR, 3.29; 95% CI, 2.07-5.25) and 2 years (RR, 9.54; 95%CI, 2.19-41.43), but not 9 weeks (RR, 0.50; 95% CI, 0.05-5.49) compared with control groups. No evidence of publication bias was observed.

CONCLUSION

Adjuvant trastuzumab therapy was strongly associated with an increased risk of significant CHF in patients with early breast cancer, particularly in 2-year use.

IMPLICATIONS FOR PRACTICE

This comprehensive meta-analysis evaluated the risk of congestive heart failure with a usage profile of adjuvant trastuzumab in patients with early breast cancer. Before initiating treatment with trastuzumab, a risk-benefit analysis for individual patients should be critically evaluated, considering that the prognosis is closely related to drug dose and duration of use. Cardiac function should be monitored throughout the treatment period and also during follow-up. Thus, early identification of trastuzumab-related cardiac dysfunction can allow effective medical intervention, elimination of symptoms, recovery of function, and continuation of trastuzumab therapy.

Inhibition of ErbB2 by herceptin reduces viability and survival, induces apoptosis and oxidative stress in Calu-3 cell line

Human epidermal growth factor receptor 2 (ErbB2) amplification and overexpression has been seen in many cancer types including non-small cell lung cancer (NSCLC). Thus, ErbB2 is an important target for cancer therapies. Increased ErbB2 expression has been associated with drug resistance in cancer cells. Herceptin is a humanized monoclonal antibody that targets the extracellular domain of ErbB2. In this study, we aimed to block ErbB2 signaling with Herceptin and assess cytotoxicity and effects on apoptosis, oxidative stress, nuclear factor kappa-B (NF-kB), and Survivin expression in Calu-3 cell line. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay were used to assess cell viability as a marker of proliferation. Acridine orange/ethidium bromide (AO/EB) staining and caspase 3/7 activity were measured as the markers of apoptosis. The relative expressions of NF-kB-p50 and Survivin mRNAs were evaluated. Activities of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT), and the levels of glutathione (GSH) and reactive oxygen species (ROS) were determined in a time- and dose-dependent manner. Our results show that Herceptin treatment inhibits cell proliferation and activates apoptosis but without effects on Survivin and NF-kB expression in Calu-3 cell line. Intracellular glutathione levels and SOD and CAT activities were decreased in a time- and dose-dependent manner associated with oxidative stress. Also, ROS were increased at 24 h. These results provide evidence that Herceptin can be used as a cytotoxic and apoptotic agent in NSCLC.