Purpose: registHER is a prospective, observational study of 1,023 newly diagnosed HER2-positive metastatic breast cancer (MBC) patients.Experimental Design: Baseline characteristics of patients with and without central nervous system (CNS) metastases were compared; incidence, time to development, treatment, and survival after CNS metastases were assessed. Associations between treatment after CNS metastases and survival were evaluated.Results: Of the 1,012 patients who had confirmed HER2-positive tumors, 377 (37.3%) had CNS metastases. Compared with patients with no CNS metastases, those with CNS metastases were younger and more likely to have hormone receptor-negative disease and higher disease burden. Median time to CNS progression among patients without CNS disease at initial MBC diagnosis (n ¼ 302) was 13.3 months. Treatment with trastuzumab, chemotherapy, or surgery after CNS diagnosis was each associated with a statistically significant improvement in median overall survival (OS) following diagnosis of CNS disease (unadjusted analysis: trastuzumab vs. no trastuzumab, 17.5 vs. 3.8 months; chemotherapy vs. no chemotherapy, 16.4 vs. 3.7 months; and surgery vs. no surgery, 20.3 vs. 11.3 months). Although treatment with radiotherapy seemed to prolong median OS (13.9 vs. 8.4 months), the difference was not significant (P ¼ 0.134). Results of multivariable proportional hazards analyses confirmed the independent significant effects of trastuzumab and chemotherapy (HR ¼ 0.33, P < 0.001; HR ¼ 0.64, P ¼ 0.002, respectively). The effects of surgery and radiotherapy did not reach statistical significance (P ¼ 0.062 and P ¼ 0.898, respectively).Conclusions: For patients with HER2-positive MBC evaluated in registHER, the use of trastuzumab, chemotherapy, and surgery following CNS metastases were each associated with longer survival.

Purpose To compare standard-of-care (SoC) trastuzumab plus chemotherapy with higher-dose (HD) trastuzumab plus chemotherapy to investigate whether HD trastuzumab increases trastuzumab serum trough concentration (C) levels and increases overall survival (OS) in first-line human epidermal growth factor receptor 2-positive metastatic gastric or gastroesophageal junction adenocarcinoma. Patients and Methods Patients with Eastern Cooperative Oncology Group performance status 2, no prior gastrectomy, and ≥ two metastatic sites were randomly assigned at a one-to-one ratio to loading-dose trastuzumab 8 mg/kg followed by SoC trastuzumab maintenance 6 mg/kg every 3 weeks or loading-dose trastuzumab 8 mg/kg followed by HD trastuzumab maintenance 10 mg/kg every 3 weeks until progression; treatment in each arm was combined with cisplatin 80 mg/m plus capecitabine 800 mg/m twice per day in cycles 1 to 6. The primary objective was HD trastuzumab OS superiority (all randomly assigned patients [full-analysis set]). Final results are from an interim analysis for futility (boundary hazard ratio [HR] ≥ 0.95) at 125 deaths. Results At clinical cutoff, 248 patients had been randomly assigned. A marked increase in mean trastuzumab C was observed after the first HD trastuzumab cycle versus SoC trastuzumab. In the full-analysis set, median OS was 12.5 months in the SoC trastuzumab arm and 10.6 months in the HD trastuzumab arm (stratified HR, 1.24; 95% CI, 0.86 to 1.78; P = .2401). Results were similar in the per-protocol set (cycle 1 trastuzumab C < 12 µg/mL). Safety was comparable between arms. Conclusion HD trastuzumab maintenance dosing was associated with higher trastuzumab concentrations, no increased efficacy, and no new safety signals. HELOISE confirms standard-dose trastuzumab (loading dose of 8 mg/kg followed by 6 mg/kg maintenance dose every 3 weeks) with chemotherapy as the SoC for first-line treatment of human epidermal growth factor receptor 2-positive metastatic gastric or gastroesophageal junction adenocarcinoma.