Effects of Trastuzumab Emtansine (T-DM1) on QT Interval and Safety of Pertuzumab Plus T-DM1 in Patients With Previously Treated Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer.

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate in development for human epidermal growth factor receptor 2 (HER2)-positive cancer. Drugs in development are generally tested for their effects on QT interval, prolongation of which is associated with the potentially fatal arrhythmia torsades de pointes. In addition, an association between left ventricular dysfunction and other HER2-directed agents has been documented. This multicenter, phase 2 study, TDM4688g, assessed the safety and pharmacokinetic characteristics of T-DM1 (3.6 mg/kg every 3 weeks) in patients with previously treated HER2-positive metastatic breast cancer, and the safety of pertuzumab plus T-DM1, an anti-HER2 extracellular domain antibody, in patients with early disease progression on T-DM1 alone. The primary end point was the change in QTc interval from baseline to each postbaseline time point, adjusted for heart rate using Fridericia's correction. T-DM1 had no clinically relevant effect on QTc interval. The observed upper limit of the one-sided 95% confidence interval was below the 10-millisecond threshold of safety concern. The safety and efficacy of single-agent T-DM1 was consistent with that observed in previous studies. Pertuzumab plus T-DM1 was generally well tolerated with no new safety signals. These results support further investigation of T-DM1 as a single agent and with pertuzumab.

Drug interaction potential of trastuzumab emtansine (T-DM1) combined with pertuzumab in patients with HER2-positive metastatic breast cancer.

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate comprised of trastuzumab and the cytotoxic agent DM1 (derivative of maytansine) linked by a stable linker N-succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC). T-DM1 targets an epitope located at subdomain IV of human epidermal growth factor receptor 2 (HER2). Pertuzumab is a monoclonal antibody that targets an epitope located at subdomain II of HER2, distinct from the epitope recognized by T-DM1. The pharmacokinetics (PK), safety, and efficacy of T-DM1 combined with pertuzumab were studied in a phase 1b/2 trial in 67 patients with HER2-positive, locally advanced or metastatic breast cancer (MBC). The therapeutic protein-drug interaction (TP-DI) potential of T-DM1 plus pertuzumab was evaluated. The PK of T-DM1-related analytes and pertuzumab were compared with historical PK data. The results show that the exposure of T-DM1 and DM1, as estimated by noncompartmental analyses, was comparable with that reported by historical single-agent studies in patients with HER2-positive MBC. T-DM1 clearance and volume of distribution in the central compartment, as estimated by population PK analysis, were also comparable between this study and historical single-agent studies in patients with HER2-positive MBC. Summary statistics of pertuzumab trough and maximal exposure (concentrations at predose and 15-30 minutes after the end of infusion at cycle 1 and at steady state) were similar with those observed in a representative historical single-agent study with the same dosing regimen. The visual predictive check plot by population simulation further confirmed that T-DM1 did not alter pertuzumab PK. Based on these data and the PK and pharmacodynamic properties of T-DM1 and pertuzumab, the risk of TP-DI appears to be low when T-DM1 and pertuzumab are given together.

Bevacizumab: an angiogenesis inhibitor for the treatment of solid malignancies.

BACKGROUND: Bevacizumab is a recombinant humanized monoclonal antibody that was approved by the US Food and Drug Administration (FDA) in February 2004 for use as part of combination therapy with fluorouracil-based regimens for metastatic colorectal cancer (mCRC). OBJECTIVES: This article reviews the mechanism of action, clinical pharmacology, and pharmacodynamic and pharmacokinetic properties of bevacizumab. It summarizes data on the clinical efficacy and tolerability of bevacizumab from Phase II/III trials in mCRC, breast cancer, non-small-cell lung cancer, and renal cell carcinoma and preliminary data from investigational studies in pancreatic cancer and soft-tissue sarcomas. The dosing and administration of bevacizumab also are discussed. METHODS: A comprehensive search of the English-language literature indexed on MEDLINE (1966-April 2006) was performed using the terms Avastin, bevacizumab, vascular endothelial growth factor, angiogenesis, and bevacizumab plus colorectal cancer, breast cancer, non-small-cell lung cancer, pancreatic cancer, and renal cell carcinoma. Published abstracts from American Society of Clinical Oncology annual meetings from 2002 to 2006, FDA submission documents, and the product information for bevacizumab also were reviewed. Pertinent review articles, preclinical studies, and editorials and all published Phase II/III clinical trials were selected for review. The reference lists of identified articles were examined for additional publications. RESULTS: Bevacizumab exhibits linear pharmacokinetics in the dose range between 0.3 and 10 mg/kg q2-3wk and steady state, which is reached in approximately 100 days. The estimated t(1/2) of bevacizumab is approximately 20 days. After correction for body weight, clearance and V(d) are reported to be a respective 26% and 22% higher in men than in women. Statistical analyses have not been performed, however, and the clinical impact of these gender differences has not been assessed. No dose adjustment is currently recommended based on age, sex, or renal function. Bevacizumab has been reported to result in changes in exposure to concomitant chemotherapy, although formal drug-interaction studies have not been performed. Surrogate markers of disease progression or treatment response to bevacizumab have been studied, but no significant correlations with any outcome measure have been found. When combined with standard chemotherapy regimens, bevacizumab has been associated with significant improvements compared with chemotherapy alone in the efficacy end points of overall survival, progression-free survival, and response rates in patients with mCRC (all, P < 0.05). Based on these findings, bevacizumab is considered a first-line option for this disease. Combination bevacizumab regimens have been associated with clinical activity in breast cancer, non-small-cell lung cancer, renal cell carcinoma, pancreatic cancer, and soft-tissue sarcoma. The observed toxicities of bevacizumab include hypertension, proteinuria, mild to moderate hemorrhage, wound healing complications, and thromboembolic events. A bevacizumab dose of 5 mg/kg q2wk has been established as effective and well tolerated in the setting of mCRC. A variety of dosing schemes have been investigated in other solid neoplasms, but no consensus has been reached on the optimal bevacizumab regimen. CONCLUSIONS: Bevacizumab is effective and generally well tolerated as first-line therapy for mCRC. The results from clinical studies of bevacizumab as a single agent or as part of combination regimens for breast cancer, non-small-cell lung cancer, renal cell carcinoma, and other solid malignancies have been promising. The most effective regimens for various malignancies and predictive markers of treatment response have not been fully determined. Combining bevacizumab with chemotherapy or other novel targeted agents appears to be a rational approach that may enhance efficacy while limiting the traditional nonselective toxicities.