Purpose:To evaluate safety and efficacy of trastuzumab with pertuzumab in patients with human epidermal growth factor receptor 2 (HER2)^positive metastatic breast cancer who had progressive disease on trastuzumab-based therapy. Experimental Design: Patients with measurable HER2 + metastatic breast cancer, V3 trastuzumab-based regimens, and left ventricular ejection fraction (LVEF) z55% received 8 or 6 mg/kg trastuzumab and 840 mg pertuzumab i.v. followed by 6 mg/kg trastuzumab and 420 mg pertuzumab every 3 weeks. Cardiac evaluation and tumor response were assessed every 3 and 6 weeks, respectively. Results: Eleven patients received 64 cycles of trastuzumab plus pertuzumab. A total of 92 echocardiograms and 8 cardiac magnetic resonance imaging studies were done.With the lower limit of normal LVEF 55%, left ventricular systolic dysfunction was observed in six patients,

The application of modeling and simulation techniques is increasingly common in the preclinical stages of the drug development process.is a potent second-generation antagonist of inhibitor of apoptosis (IAP) proteins that is being developed for the treatment of various cancers. GDC-0917 has low to moderate clearance in the mouse (12.0 ml/min/ kg), rat (27.0 ml/min/kg), and dog (15.3 ml/min/kg), and high clearance in the monkey (67.6 ml/min/kg). Accordingly, oral bioavailability was lowest in monkeys compared with other species. Based on our experience with a prototype molecule with similar structure, in vitroin vivo extrapolation was used to predict a moderate clearance (11.5 ml/min/kg) in humans. The predicted human volume of distribution was estimated using simple allometry at 6.69 l/kg. Translational pharmacokinetic-pharmacodynamic (PK-PD) analysis using results from MDA-MB-231-X1.1 breast cancer xenograft studies and predicted human pharmacokinetics suggests that ED 50 and ED 90 targets can be achieved in humans using acceptable doses (72 mg and 660 mg, respectively) and under an acceptable time frame. The relationship between GDC-0917 concentrations and pharmacodynamic response (cIAP1 degradation) was characterized using an in vitro peripheral blood mononuclear cell immunoassay. Simulations of human GDC-0917 plasma concentration-time profile and cIAP1 degradation at the 5-mg starting dose in the phase 1 clinical trial agreed well with observations. This work shows the importance of leveraging information from prototype molecules and illustrates how modeling and simulation can be used to add value to preclinical studies in the early stages of the drug development process.

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