Efficacy and safety of the combination of metformin, everolimus and exemestane in overweight and obese postmenopausal patients with metastatic, hormone receptor-positive, HER2-negative breast cancer: a phase II study.

Background Increased adiposity is thought to result in worse clinical outcomes in patients with breast cancer through increased estrogen production, hyperinsulinemia, insulin resistance, and activation of the phosphatidylinositol-3-kinase/AKT/mammalian target of rapamycin (mTOR) pathway. Thus, we hypothesized that the addition of metformin to everolimus and exemestane, could lead to better outcomes in overweight and obese patients with metastatic, hormone receptor-positive, HER2-negative breast cancer. We conducted a phase II trial to evaluate the efficacy and safety of the combination of metformin, everolimus and exemestane in overweight and obese postmenopausal women with metastatic, hormone receptor-positive, HER2-negative breast cancer. Methods Twenty-two patients with a body mass index ≥25 kg/m2 were treated with metformin 1000 mg twice daily, everolimus 10 mg daily and exemestane 25 mg daily. Median progression-free (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Results Median PFS and OS were 6.3 months (95% confidence interval [CI]: 3.8-11.3 months) and 28.8 months (95% CI: 17.5-59.7 months), respectively. Five patients had a partial response and 7 had stable disease for ≥24 weeks yielding a clinical benefit rate of 54.5%. Compared with overweight patients, obese patients had an improved PFS on univariable (p = 0.015) but not multivariable analysis (p = 0.215). Thirty-two percent of patients experienced a grade 3 treatment-related adverse event (TRAE). There were no grade 4 TRAEs and 7 patients experienced a grade 3 TRAE. Conclusion The combination of metformin, everolimus and exemestane was safe and had moderate clinical benefit in overweight and obese with patients metastatic, hormone receptor-positive, HER2-negative breast cancer.

Effect of adjuvant/neoadjuvant trastuzumab on clinical outcomes in patients with HER2-positive metastatic breast cancer.

BACKGROUND: The purpose of the current study was to describe the outcomes of patients with human epidermal growth factor receptor 2 (HER2)-overexpressed/amplified (HER2+) early breast cancer who received adjuvant or neoadjuvant trastuzumab-based therapy and were subsequently retreated with trastuzumab for metastatic disease. METHODS: A total of 353 patients with metastatic HER2+ breast cancer who were treated with trastuzumab as part of their first-line treatment for metastatic disease were identified. A total of 75 patients had received adjuvant or neoadjuvant trastuzumab-based therapy for early breast cancer, and 278 had not. Clinical outcomes of patients who had or had not received prior trastuzumab were compared using Cox proportional hazards regression and logistic regression analyses. Survival was estimated using the Kaplan-Meier method. RESULTS: The clinical benefit (complete response, partial response, or stable disease of ≥ 6 months) rates were 71% in the group who did not receive prior trastuzumab and 39% in the group previously treated with trastuzumab. The adjusted odds ratios were 0.28 (95% confidence interval [95% CI], 0.13-0.59; P = .0009) for clinical benefit rates and 0.39 (95% CI, 0.18-0.82; P = .038) for objective (complete or partial) response rates. In the univariate analysis, the median overall survival rate was longer in the group who did not receive prior trastuzumab (36 months vs 28 months) (hazards ratio, 1.47; 95% CI, 1.07-2.01 [P = .022]). The multivariate analysis found no significant difference in overall survival. CONCLUSIONS: When treated with trastuzumab for metastatic disease, patients with HER2+ breast cancer without prior exposure to trastuzumab were found to have superior clinical outcomes to those with prior exposure. Prior trastuzumab exposure should be considered in treatment algorithms and in HER2-targeted clinical trial enrollment for metastatic disease.