Publications by authors named "Bert L Lum"

The US Food and Drug Administration (FDA) issued a guidance document in 2010 on pharmacokinetic (PK) studies in renal impairment (RI) on the basis of observations that substances such as uremic toxins might result in altered drug metabolism and excretion. No specific recommendations for oncology drugs were included. We surveyed the publicly available FDA review documents of 29 small molecule oncology drugs approved between 2010 and the first quarter of 2015.

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Purpose: The NeoSphere trial evaluated pertuzumab in the neoadjuvant setting [early breast cancer (EBC)] with pathological complete response (pCR) as the primary efficacy end point. This analysis of pertuzumab aimed to (1) compare its pharmacokinetics (PK) in patients with EBC versus advanced cancers, (2) to further evaluate PK drug-drug interactions (DDIs) when given in combination with trastuzumab, and (3) to assess the relationship between exposure and efficacy to assess the clinical dosing regimen in the EBC patients.

Methods: Pertuzumab serum concentration data from 180 patients in NeoSphere were compared to historical observations and potential DDI was assessed, by applying simulation techniques using a population PK model.

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Apo2L/TRAIL is a member of the tumor necrosis factor superfamily and an important inducer of apoptosis. Recombinant human (rhu) Apo2L/TRAIL has been attractive as a potential cancer therapeutic because many types of tumor cells are sensitive to its apoptosis-inducing effects. Nonclinical toxicology studies were conducted to evaluate the safety of rhuApo2L/TRAIL for possible use in humans.

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The maximally tolerated dose (MTD) of cytotoxic agents has historical precedence in treating cancer, as it was believed that dose and therapeutic effect are intrinsically linked and that the MTD would provide greatest therapeutic value. With molecularly targeted agents, the premise of preventing toxicity to normal tissues while modulating tumor growth provides a potential for an increased therapeutic window. Results from these targeted agents suggest we are entering an era of chronic cancer management, which will require design of regimens with long-term tolerability.

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Purpose: To characterize the population pharmacokinetics (PKs) of subcutaneous (SC) and intravenous (IV) trastuzumab in early breast cancer (EBC), assess the impact of covariates on trastuzumab PK, and evaluate fixed (nonweight-based) dosing for the SC regimen administrated via handheld syringe.

Methods: Serum trastuzumab concentrations from 595 patients with HER2-positive EBC in the HannaH study (fixed 600 mg SC trastuzumab or weight-based IV trastuzumab) were analyzed using nonlinear mixed-effects modeling. Multiple logistic regression was used to assess the exposure-response relationships between PK, efficacy [pathologic complete response (pCR)], and safety [grade ≥3 adverse events (AEs)].

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The aim of this study was to evaluate the effect of coadministration of acid-reducing agents on the pharmacokinetic exposure of orally administered epidermal growth factor receptor inhibitor erlotinib, a drug that displays pH-dependent solubility. Two studies were conducted, the first with the proton pump inhibitor omeprazole and the second with the H2-receptor antagonist ranitidine. Twenty-four healthy male and female volunteers were enrolled in each study.

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The objective of this study was to evaluate the potential for a pharmacokinetic (PK) drug-drug interaction (DDI) between trastuzumab and carboplatin and to evaluate the potential effect of trastuzumab on the electrocardiogram QT interval. Here, we report the results of the PK DDI assessment and an interim safety analysis. Patients with metastatic or locally advanced, inoperable, human epidermal growth factor receptor 2-positive cancer received docetaxel and carboplatin on cycle 1, day 1 and then on day 1 of each subsequent 3-weekly treatment cycle.

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Purpose: This study evaluated the potential effect of trastuzumab on the electrocardiogram (ECG) QT interval and assessed the potential pharmacokinetic interaction between trastuzumab and carboplatin. Here, we report the QT and safety results.

Methods: Patients with metastatic or inoperable HER2-positive solid tumors received docetaxel and carboplatin on Day 1 of each 3-week (q3w) cycle.

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In vitro, erlotinib (0-30 µmol/l) and C-labelled midazolam (MDZ) (5 µmol/l) were incubated with human liver microsomes; separately, microsomes were preincubated with erlotinib (10 µmol/l) before the addition of MDZ. Results showed a time-dependent inhibition of MDZ metabolism by erlotinib, with a Ki of 7.5 µmol/l and an inactivation rate constant of 0.

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Purpose: The aim of this study was to characterize trastuzumab population pharmacokinetics (PKs) in patients with human epidermal growth factor receptor 2-positive advanced gastric or gastroesophageal junction cancer and the relationship of trastuzumab PK with patient response.

Methods: A nonlinear mixed effects PK model was built using data from the ToGA study. Patients were randomized to intravenous trastuzumab plus chemotherapy or chemotherapy alone.

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Purpose: Erlotinib, N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy) quinazolin-4-amine is approved for the treatment for non-small cell lung cancer and pancreatic cancer. Because erlotinib is metabolized predominately by CYP3A4, co-administration of compounds that increase CYP3A4 activity may alter the efficacy and safety of erlotinib therapy. Two phase I studies were conducted in healthy male subjects to evaluate the effect of pre- or co-administered rifampicin, a CYP3A4 inducer, on the pharmacokinetics of erlotinib.

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Purpose: To demonstrate pharmacokinetic (PK) comparability for a single dose of 600 mg subcutaneous (SC) trastuzumab, administered via a novel single-use injection device (SID) or handheld syringe in 119 randomized healthy male subjects.

Methods: The co-primary PK endpoints area under the time-concentration curve from the start of dosing to day 22 (AUC(0-21 days)) and maximum observed trastuzumab serum concentration (C(max)) were dose-normalized and body-weight-adjusted, and compared using geometric mean ratios (GMRs). SID performance, injection site pain, adverse events, and antidrug antibodies (ADAs) were assessed.

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Acid-reducing agents (ARAs) are the most commonly prescribed medications in North America and Western Europe. There are currently no data describing the prevalence of their use among cancer patients. However, this is a paramount question due to the potential for significant drug-drug interactions (DDIs) between ARAs, most commonly proton pump inhibitors (PPIs), and orally administered cancer therapeutics that display pH-dependent solubility, which may lead to decreased drug absorption and decreased therapeutic benefit.

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Pertuzumab is a novel antihuman epidermal growth factor receptor 2 (HER2) humanized monoclonal antibody. Combined with trastuzumab plus docetaxel, pertuzumab improved progression-free and overall survival versus trastuzumab plus docetaxel in the phase III CLEOPATRA trial (NCT00567190) in first-line HER2-positive metastatic breast cancer. Thirty-seven patients participated in a pharmacokinetic (PK)/corrected QT interval substudy of CLEOPATRA, which evaluated potential PK drug-drug interaction (DDI).

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The therapeutic rationale of antibody conjugates is the selective delivery of a cytotoxin to tumor cells via binding and internalization of the monoclonal antibodies to a specific cell-surface antigen, thereby enhancing the therapeutic index of the cytotoxin. The key structural and functional components of an antibody conjugate are the antibody, the linker and the cytotoxin (chemical or radionuclide) with each component being critical for the successful development of the conjugate. Considerable efforts have been made in understanding the pharmacokinetics, pharmacodynamics, tissue distribution, metabolism and pharmacologic effects of these complex macromolecular entities.

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What Is Already Known About This Subject: While recent publications have suggested the pharmacokinetics (PK) of vismodegib appear to be non-linear, there has not been a report describing the mechanisms of non-linearity.

What This Study Adds: This study provides evidence that two separate processes, namely, solubility-limited absorption and concentration-dependent plasma protein binding, can explain the non-linear PK of vismodegib. This study provides quantitative results which can account for the lower than expected accumulation of vismodegib with continuous daily dosing.

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Vismodegib (GDC-0449), a small-molecule Hedgehog pathway inhibitor, was well tolerated in patients with solid tumors and showed promising efficacy in advanced basal cell carcinoma in a Phase I trial. The purpose of the study presented here was to determine routes of elimination and the extent of vismodegib metabolism, including assessment and identification of metabolites in plasma, urine, and feces. Six healthy female subjects of nonchildbearing potential were enrolled; each received a single 30-ml oral suspension containing 150 mg of vismodegib with 6.

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Vismodegib (GDC-0449) is is an orally available selective Hedgehog pathway inhibitor in development for cancer treatment. The drug is ≥95% protein bound in plasma at clinically relevant concentrations and has an approximately 200-fold longer single dose half-life in humans than rats. We have identified a strong linear relationship between plasma drug concentrations and α-1-acid glycoprotein (AAG) in a phase I study.

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Purpose: In a phase I trial for patients with refractory solid tumors, hedgehog pathway inhibitor vismodegib (GDC-0449) showed little decline in plasma concentrations over 7 days after a single oral dose and nonlinearity with respect to dose and time after single and multiple dosing. We studied the role of GDC-0449 binding to plasma protein alpha-1-acid glycoprotein (AAG) to better understand these unusual pharmacokinetics.

Experimental Design: Sixty-eight patients received GDC-0449 at 150 (n = 41), 270 (n = 23), or 540 (n = 4) mg/d, with pharmacokinetic (PK) sampling at multiple time points.

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Purpose: Apoptosis ligand 2/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL)-a member of the tumor necrosis factor cytokine family-induces apoptosis by activating the extrinsic pathway through the proapoptotic death receptors DR4 and DR5. Recombinant human Apo2L/TRAIL (rhApo2L/TRAIL) has broad potential as a cancer therapy. To the best of our knowledge, this is the first in-human clinical trial to assess the safety, tolerability, pharmacokinetics, and antitumor activity of multiple intravenous doses of rhApo2L/TRAIL in patients with advanced cancer.

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Background: Valspodar, a non-immunosuppressive analog of cylosporine, is a potent P-glycoprotein (MDR1) inhibitor. As MDR1-mediated efflux of chemotherapeutic agents from leukemic blasts may contribute to drug resistance, a phase 1 study of valspodar combined with mitoxantrone and etoposide in pediatric patients with relapsed or refractory leukemias was performed.

Procedure: Patients received a valspodar-loading dose (2 mg/kg) followed by a 5-day continuous valspodar infusion (8, 10, 12.

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Purpose: To assess the pharmacokinetics and evaluate potential drug-drug interactions between erlotinib, paclitaxel and carboplatin.

Experimental Design: 1,079 previously untreated patients with advanced NSCLC were enrolled and randomized in a phase III trial (TRIBUTE) to receive either erlotinib or placebo in combination with paclitaxel 200 mg/m2 IV over 3 h and carboplatin at a calculated dose to achieve an AUC 6 mg∙min/mL. To determine possible drug-drug interaction with this combination, a subset of 24 (12 erlotinib, 12 placebo) patients were enrolled onto an intensive pharmacokinetic (IPK) substudy group at a single site.

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Background: This phase I/II trial was conducted to determine the toxicities, recommended dose, pharmacokinetics, and response rate of erlotinib plus trastuzumab in metastatic HER2+ breast cancer.

Patients And Methods: In phase I, sequential groups of patients with unlimited previous treatment received erlotinib at dose levels of 50, 100, and 150 mg plus standard dose weekly trastuzumab. In phase II, only patients with no previous chemotherapy or trastuzumab in the metastatic setting were allowed.

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The effects of food on the pharmacokinetics of erlotinib were investigated in two open-label, randomized studies. In a single-dose crossover study (n = 18), 150 mg of erlotinib was administered under either fasting or fed conditions. In the first period, an approximate doubling in the area under the plasma concentration-time curve was evidenced by the geometric mean ratio (GMR) of 2.

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Background: Erlotinib is an orally active antitumor agent. Analyses in vitro using human liver microsomes and recombinant enzymes showed that erlotinib was metabolized primarily by CYP3A4, with a secondary contribution from CYP1A2.

Methods: A computer-based simulation model, SimCYP, predicted that CYP3A4 contributed to approximately 70% of the metabolic elimination of erlotinib, with CYP1A2 being responsible for the other approximately 30%.

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