Phase II feasibility and pharmacokinetic study of concurrent administration of trastuzumab and high-dose chemotherapy in advanced HER2+ breast cancer

Pharmacokinetic drug-drug interaction potentials for therapeutic monoclonal antibodies: reality check

A formal assessment of the drug-drug interaction potential of any investigational drug product often requires multiple metabolic and pharmacokinetic evaluations. In contrast to a small-molecule drug, investigating the drug-drug interaction potential of a monoclonal antibody is inherently complicated. High molecular weight monoclonal antibodies are often genetically engineered to demonstrate strong specificity for a particular human antigen target. Consequently, monoclonal antibodies usually have few clinically relevant animal models--other than nonhuman primates--in which to conduct appropriate nonclinical studies. Likewise, clinical drug-drug interaction studies of monoclonal antibodies with long elimination half-lives pose definite operational challenges as conventional crossover studies with adequate washout periods are difficult to conduct. Furthermore, the current regulatory guidance on the design and conduct of in vitro and in vivo drug-drug interaction studies applies more readily to small-molecule drugs than protein-based biologics. Nevertheless, a certain amount of clinically useful information has begun to emerge from the published literature on drug-drug interaction potentials of therapeutic monoclonal antibodies. This article provides a systematic review of the current literature and offers some practical considerations for the design and conduct of pharmacokinetic drug-drug interaction assessments involving novel monoclonal antibodies. Ideally, these evaluations should be performed throughout all stages of drug development. In particular, pharmacokinetic interaction studies with any marketed drugs that are likely to be coadministered with the monoclonal antibody will yield the most clinically useful information for practitioners and patients alike.

Trastuzumab: a review of its use in the management of HER2-positive metastatic and early-stage breast cancer

Trastuzumab (Herceptin) is a humanised monoclonal antibody used in the treatment of breast cancer that overexpresses human epidermal growth factor receptor 2 (HER2), which is associated with clinically aggressive disease and a poor prognosis. The addition of intravenous trastuzumab to first-line chemotherapy improved the time to disease progression, objective response rate, duration of response, and overall survival in randomised, multicentre trials in women with HER2-positive metastatic breast cancer. As such, trastuzumab has become the standard of care in this setting, despite its high acquisition cost and potential for cardiac events, and is licensed for use in combination with paclitaxel (Europe and the US) or docetaxel (Europe). In addition, trastuzumab monotherapy is approved for use in patients with HER2-positive metastatic breast cancer who have previously received chemotherapy for their metastatic disease. Recent data from large phase III trials with trastuzumab in the adjuvant setting revealed significant improvements in disease-free and overall survival. Thus, trastuzumab is also rapidly becoming a standard component of adjuvant therapy for patients with HER2-positive early-stage breast cancer.

Combinatorial synergy induced by adenoviral-mediated mda-7 and Herceptin in Her-2+ breast cancer cells

The melanoma differentiation-associated gene-7 (mda-7) is a member of the interleukin-10 cytokine family and a novel tumor suppressor gene. Adenoviral-mediated mda-7 (Ad-mda7) gene transfer has tumor-specific growth inhibitory and proapoptotic effects in a broad spectrum of cancer cells. In breast cancer cells, adenoviral-induced mda-7 expression triggers antiproliferative effects by downregulation of survival signals, such as Bcl-2 and Akt. The anti-human epidermal growth factor receptor-2 (Her-2) monoclonal antibody, Trastuzumab (Herceptin), increases the sensitivity of Her-2/neu-overexpressing breast cancer cells to chemotherapeutic agents and radiotherapy. In this study, we evaluate the effects of treatment with Ad-mda7 and Herceptin combination therapy in a panel of Her-2/neu-overexpressing cell lines, and in established tumors in nude mice. Compared to individual treatments, the combination of Ad-mda7 and Herceptin elicits supra-additive antitumor activity in Her-2/neu-overexpressing tumor cell lines: increased cell death, cell cycle block and apoptosis. The Ad-mda7 and Herceptin interaction was shown to be synergistic by isobologram analysis. Ad-mda7 does not alter cell surface Her-2/neu levels, but the combination of Ad-mda7+Herceptin results in increased expression of cell surface E-cadherin with concomitant translocation of beta-catenin from the nucleus to the cell membrane. In vivo, the combination of Ad-mda7 and Herceptin showed significantly increased antitumor activity (P<0.003) against Her-2/neu-overexpressing tumors. These data suggest that the combination of Ad-mda7 with Herceptin may be a novel therapy for breast cancer patients whose tumors overexpress Her-2/neu. The observed synergistic effect may improve treatment options for otherwise poorly responsive, Her-2-positive, breast cancer patients.

Cardiac toxicity of trastuzumab in metastatic breast cancer patients previously treated with high-dose chemotherapy: a retrospective study

HER-2 overexpression is associated to a poor prognosis in high-risk and metastatic breast cancer (MBC) patients treated with high-dose chemotherapy (HDC). HER-2 status is also a predictive factor and when trastuzumab is administered in combination with or sequentially to chemotherapy, a significant disease-free and/or overall survival improvement has been observed in HER-2+ early and MBC. Unfortunately, in both settings, trastuzumab is associated with an increased risk of cardiac dysfunction (CD). We have reviewed the clinical charts of HER-2-overexpressing MBC patients treated with trastuzumab after HDC. Age, baseline left ventricular ejection fraction (LVEF), radiation therapy on cardiac area, exposure to anthracycline, single or multiple transplant, high-dose agents, trastuzumab treatment duration were recorded as potential risk factors. In total, 53 patients have been included in the analysis. Median LVEF at baseline was 60.5%; at the end of trastuzumab (data available for 28 patients only), it was 55% (P = 0.01). Five out of the 28 (17.9%) patients experienced CD. Two out of 53 (3.8%) patients developed a congestive heart failure. Age > or = 50 years and multiple transplant procedure were potential risk factors for CD. The overall incidence of CD observed in this population of HER-2+ MBC patients treated with trastuzumab after HDC is not superior to that reported with concomitant trastuzumab and anthracyclines. However, patients with age > or = 50 years or receiving multiple course of HDC should be considered at risk for CD.

Metabolism and transport of oxazaphosphorines and the clinical implications

The oxazaphosphorines including cyclophosphamide (CPA), ifosfamide (IFO), and trofosfamide represent an important group of therapeutic agents due to their substantial antitumor and immuno-modulating activity. CPA is widely used as an anticancer drug, an immunosuppressant, and for the mobilization of hematopoetic progenitor cells from the bone marrow into peripheral blood prior to bone marrow transplantation for aplastic anemia, leukemia, and other malignancies. New oxazaphosphorines derivatives have been developed in an attempt to improve selectivity and response with reduced toxicity. These derivatives include mafosfamide (NSC 345842), glufosfamide (D19575, beta-D-glucosylisophosphoramide mustard), NSC 612567 (aldophosphamide perhydrothiazine), and NSC 613060 (aldophosphamide thiazolidine). This review highlights the metabolism and transport of these oxazaphosphorines (mainly CPA and IFO, as these two oxazaphosphorine drugs are the most widely used alkylating agents) and the clinical implications. Both CPA and IFO are prodrugs that require activation by hepatic cytochrome P450 (CYP)-catalyzed 4-hydroxylation, yielding cytotoxic nitrogen mustards capable of reacting with DNA molecules to form crosslinks and lead to cell apoptosis and/or necrosis. Such prodrug activation can be enhanced within tumor cells by the CYP-based gene directed-enzyme prodrug therapy (GDEPT) approach. However, those newly synthesized oxazaphosphorine derivatives such as glufosfamide, NSC 612567 and NSC 613060, do not need hepatic activation. They are activated through other enzymatic and/or non-enzymatic pathways. For example, both NSC 612567 and NSC 613060 can be activated by plain phosphodiesterase (PDEs) in plasma and other tissues or by the high-affinity nuclear 3'-5' exonucleases associated with DNA polymerases, such as DNA polymerases and epsilon. The alternative CYP-catalyzed inactivation pathway by N-dechloroethylation generates the neurotoxic and nephrotoxic byproduct chloroacetaldehyde (CAA). Various aldehyde dehydrogenases (ALDHs) and glutathione S-transferases (GSTs) are involved in the detoxification of oxazaphosphorine metabolites. The metabolism of oxazaphosphorines is auto-inducible, with the activation of the orphan nuclear receptor pregnane X receptor (PXR) being the major mechanism. Oxazaphosphorine metabolism is affected by a number of factors associated with the drugs (e.g., dosage, route of administration, chirality, and drug combination) and patients (e.g., age, gender, renal and hepatic function). Several drug transporters, such as breast cancer resistance protein (BCRP), multidrug resistance associated proteins (MRP1, MRP2, and MRP4) are involved in the active uptake and efflux of parental oxazaphosphorines, their cytotoxic mustards and conjugates in hepatocytes and tumor cells. Oxazaphosphorine metabolism and transport have a major impact on pharmacokinetic variability, pharmacokinetic-pharmacodynamic relationship, toxicity, resistance, and drug interactions since the drug-metabolizing enzymes and drug transporters involved are key determinants of the pharmacokinetics and pharmacodynamics of oxazaphosphorines. A better understanding of the factors that affect the metabolism and transport of oxazaphosphorines is important for their optional use in cancer chemotherapy.

Prognostic analysis of pre-transplant peripheral T-cell levels in patients receiving an autologous hematopoietic progenitor-cell transplant

The purpose of this study was to evaluate pre-transplant T-cell status in autologous hematopoietic progenitor-cell transplantation (HPCT) recipients. Between 1999 and 2002 we prospectively enrolled 85 autologous HPCT recipients with solid tumors (N = 50) or hematological malignancies (n = 35). Patient diagnoses included breast cancer (N = 49), non-Hodgkin's lymphoma (N = 20), myeloma (N = 11), Hodgkin's disease (N = 3), germ-cell tumor (N = 1) and amyloidosis (N = 1). Levels of CD3, CD4, CD8, memory and naïve CD4, and CD8 T-cell subsets were analyzed before autologous HPCT. Autologous HPCT recipients presented with lower pre-transplant counts of CD3, CD4, but not CD8 T cells, as compared to healthy controls. Pre-transplant CD4 T-cell levels correlated with progression-free survival (PFS) (P = 0.002) and overall survival (OS) (P = 0.05), in patients with hematologic malignancies (P = 0.02) and breast cancer (P = 0.04). Specifically, pre-transplant memory CD4 + CD45RA - CD62L - T-cell levels correlated with PFS (P = 0.01). The prognostic effects of pre-transplant CD4 and CD4 + CD45RA - CD62L - T cells were independent of tumor diagnosis, tumor stage, tumor sensitivity, and, for breast cancer patients, Her2 / neu status. Our results suggest that pre-transplant CD4 T-cell status, specifically CD4 + CD45RA - CD62L - memory T cells, correlates with the outcome of autologous HPCT recipients. These observations suggest the feasibility of prospective identification of those patients at higher risk of relapse, based on their immune status.