Related CCR Translation from Pharmacokinetics of Hedgehog Pathway Inhibitor Vismodegib (GDC-0449) in Patients with Locally Advanced or Metastatic Solid Tumors: the Role of Alpha-1-Acid Glycoprotein Binding

Background: Polycystic kidney disease (PKD) is a common hereditary disorder with an incidence of 1:700 to 1:1000 for the autosomal dominant polycystic kidney disease (ADPKD) and 1:10,000 for the autosomal recessive (ARPKD) forms. The epithelial growth factor (EGFR) axis may play a role in both forms by promoting epithelial cell proliferation and cyst formation. Objectives: To characterize the plasma and tissue pharmacokinetics (PK), and cellular distribution of the oral EGFR inhibitor, erlotinib, in the Hanover-Sprague Dawley (Han:SPRD) heterozygote rat model of ADPKD to support preclinical development strategies. Methods: Twenty-one Han:SPRD heterozygous male rats were administered a single erlotinib dose of 15 mg/kg with concentrations erlotinib and its’ major metabolite, OSI-420 determined in plasma and tissues using LC-MS/MS. To assess cellular distribution, microautoradiography was performed following a single oral dose of [C] erlotinib (15 mg/kg, ~200 μCi/kg). Results: Following dosing, erlotinib readily appeared in plasma and distributed into the renal tissue and PKD cysts at concentrations that were approximately 1.5-fold higher than the plasma compartment. Cellular distribution studies demonstrated that radioactivity associated with erlotinib was localized into the cyst lumen of the Han:SPRD rat model. The observed plasma concentrations are consistent with those observed in cancer patients. Conclusion: Oral erlotinib in the Han:SPRD rat model demonstrated measurable concentrations in plasma and preferential distribution into renal tissue and cysts, suggesting a potential role in the treatment of PKD and further supports additional nonclinical studies including PK, target modulation, and PK/PD modeling to define the dose and schedules for clinical development in PKD.

Pharmacokinetic (PK) variability in cancer clinical trials may be due to heterogeneous populations and identifying sources of variability is important. Use of healthy subjects in clinical pharmacology studies together with detailed knowledge of the characteristics of patients with cancer can allow for quick identification and quantification of factors affecting PK variability. PK data and sources of variability of 40 marketed molecularly targeted oncology therapeutics were compiled from regulatory approval documents covering an 18‐year period (1999–2017). Variability in PK parameters was compared and contributors to variability were identified. The results show that PK variability was ~ 16% higher for peak plasma concentration (Cmax) and area under the concentration time curve (AUC) in patients with cancer compared with healthy subjects. Several factors were identified as major contributors to variability including hepatic/renal impairment and cytochrome P450 inhibition/induction. Lower PK variability in healthy subjects may represent an opportunity to perform rapid and robust pharmacological and PK assessments to inform subsequent studies in the development of new cancer therapies.

The aim of the study was to characterize the population pharmacokinetics (PK) of the intravenous formulation of trastuzumab, assess the impact of patient and pathological covariates on trastuzumab PK, and perform simulations to support dosing recommendations in special situations.

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.

2525 Background: The aim of this analysis was to develop a PPK model for IV trastuzumab (Herceptin), to assess the impact of patient covariates on PK, and perform simulations to support dosing recommendations. Methods: Serum trastuzumab concentration data (26,040 samples) from 1582 patients with metastatic breast cancer (MBC), early breast cancer (EBC), advanced gastric cancer (AGC) or other tumor types, and 6 healthy volunteers in 18 Phase I, II, and III trials were analyzed using nonlinear mixed-effects modeling (NONMEM). Monte Carlo simulations were performed using the NONMEM PK parameter estimates (with variability) to inform dosing recommendations. Results: A two-compartment model with parallel linear and nonlinear elimination best described the data. Significant covariates (P < 0.001) influencing linear CL were baseline weight, SGOT, albumin, primary tumor type, and presence of liver metastases. MBC had similar PK parameters as EBC, with lower distributions of Cmin,ss in MBC explained by covariates. The higher linear CL in AGC patients resulted in a 30.5% lower Cmin,ss. Simulations for drug washout indicated that 95% of patients with breast cancer (BC) reach trastuzumab concentrations < 1 µg/mL (~97% washout) at ≤7 months. Simulations also indicated that a missed dose of trastuzumab in BC or AGC patients of ≤1 week did not result in a long PK under-exposure (i.e. the trastuzumab concentration is within 15% of Cmin,ss by 3 weeks) but a missed dose of > 1 week took approximately 6 weeks to get back within the steady-state exposure range. Conclusions: Trastuzumab PK was well described by a two-compartment model with parallel linear and nonlinear eliminationacross cancer types, disease status, and regimens. No dose adjustment is required based on any of the identified patient covariates (e.g. weight, tumor type). Simulations using the PPK model informed the prescribing information for Herceptin; trastuzumab has a 7-month serum washout period during which patients should avoid an anthracycline-based therapy, pregnancy, or breastfeeding. A re-loading dose is required if a maintenance dose is missed by > 1 week to maintain serum concentrations.

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. The objectives were as follows: (i) summarize the impact of RI on PK at the time of the initial new drug application; (ii) identify limitations of the guidance; and (iii) outline an integrated approach to study the impact of RI on these drugs. Our survey indicates that the current FDA guidance does not appear to provide clear strategic or decision pathways for RI studies in terms of small molecule oncology drugs. The FDA review documents indicate an individualized approach to the review because of the complex pharmacologic nature of these drugs and patient populations. Overall, the strategy for carrying out a RI study during clinical development or as a postmarketing study requires integration with the totality of data, including mass balance, absolute bioavailability, drug-drug interaction, hepatic dysfunction, population PK, exposure-response analysis, the therapeutic window for best guidance, and determination of the optimal doses for special oncology populations.

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. The cynomolgus monkey was chosen for this safety assessment based on high protein sequence homology between human and cynomolgus Apo2L/TRAIL and comparable expression of their receptors. Although hepatotoxicity was observed in repeat-dose monkey studies with rhuApo2L/TRAIL, all animals that displayed hepatotoxicity had developed antitherapeutic antibodies (ATAs). The cynomolgus ATAs augmented the cytotoxicity of rhuApo2L/TRAIL but not of its cynomolgus counterpart. Of note, human and cynomolgus Apo2L/TRAIL differ by four amino acids, three of which are surface-exposed. In vivo studies comparing human and cynomolgus Apo2L/TRAIL supported the conclusion that these distinct amino acids served as epitopes for cross-species ATAs, capable of crosslinking rhuApo2L/TRAIL and thus triggering hepatocyte apoptosis. We describe a hapten-independent mechanism of immune-mediated, drug-related hepatotoxicity - in this case - associated with the administration of a human recombinant protein in monkeys. The elucidation of this mechanism enabled successful transition of rhuApo2L/TRAIL into human clinical trials.

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. A corresponding switch from MTD-based (toxicity-driven) dosing strategies to alternative paradigms is also expected. The challenge with these targeted agents is to fully understand the complex relationship between pharmacokinetics, pharmacodynamics, and safety and efficacy in early-stage trials, so that the optimal dose and schedule for registration trials may be identified. This review provides a systematic survey of the applications submitted to the United States Food and Drug Administration (FDA) for oncology indications, from 2010 through early 2015, and summarizes the dose selection rationale for registrational trials, the relationship of the MTD to outcomes of the final label dose, the postmarketing requirements or commitments related to dose optimization activities, the role of biomarkers, and typical exposure-response modeling methods.

Therapeutic drug monitoring (TDM) aims to maintain circulating drug concentrations at a desired level to optimize clinical outcome. The vast majority of marketed drugs do not require TDM, suggesting the clinical benefit of TDM has not been sufficiently demonstrated in most cases. With the continued emergence and prominence of monoclonal antibodies (mAbs) as drugs, especially in inflammation and cancer therapeutic areas, we are at a juncture to consider applicability of TDM for mAbs.

Analyzing Patient-Reported Outcomes in Breast Cancer through Item-Response Theory Pharmacometric Modeling

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.

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. Erlotinib was administered as a single oral 150mg dose on day 1. After the washout a subsequent study period evaluated 150mg erlotinib administered with the acid-reducing agent. Omeprazole (40 mg once daily) was given on days 11-14, concomitantly with erlotinib on day 15, and for two additional days (days 16-17). In the ranitidine study, on day 13, participants were randomized to either concomitant dosing (treatment B) or staggered administration (treatment C) of erlotinib and ranitidine and crossed over to the other treatment starting on day 27. For treatment B, ranitidine (300 mg once daily) was administered in the morning for 5 days, 2 h before erlotinib. For treatment C, ranitidine was administered as a divided dose (150 mg twice daily) for 5 days, with erlotinib given 10 h after the previous evening dose and 2 h before the next ranitidine morning dose. Plasma samples were obtained for determination of the concentrations of erlotinib and its metabolite OSI-420, following each erlotinib dose. All participants were monitored for safety and tolerability. The geometric mean ratios of AUC(0-infinity) and C-max for erlotinib and AUC(0-last) and C-max for OSI-420 were substantially decreased when erlotinib was dosed with omeprazole. The estimated mean ratio (90% confidence interval) for erlotinib was 0.54 (0.49-0.59) for AUC(0-infinity) and 0.39 (0.32-0.48) for C-max. For OSI-420, the estimated mean ratio was 0.42 (0.37-0.48) for AUC(0-last) and 0.31 (0.24-0.41) for C-max. AUC(0-infinity) and C-max for erlotinib were substantially decreased by 33 and 54%, respectively, upon coadministration with ranitidine, but the decrease was only 15 and 17% when ranitidine and erlotinib were given staggered. Similar results were observed for the metabolite OSI-420. Erlotinib was generally well-tolerated alone or in combination with omeprazole or ranitidine. Erlotinib pharmacokinetic exposure was substantially reduced upon coadministration with omeprazole and ranitidine, but not when administered with a staggered dosing approach to ranitidine. Therefore, it is recommended that the concomitant use of erlotinib with proton pump inhibitors be avoided. If treatment with an H2-receptor antagonist such as ranitidine is required, erlotinib must be administered 10 h after the H2-receptor antagonist dosing and at least 2 h before the next dose of the H2-receptor antagonist. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

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. Trastuzumab was administered by intravenous infusion, with an accelerated loading dose on cycle 1, day 2 and cycle 1, day 8, and then a maintenance dose on day 1 of each subsequent 3-weekly treatment cycle. Blood was collected at various time points to assess free (unbound) plasma carboplatin and serum trastuzumab PK. The study enrolled 59 patients. Carboplatin concentrations in the presence and absence of trastuzumab were similar, as demonstrated by the geometric mean ratios for PK parameters, which were close to 1.0 (no effect). The observed trastuzumab concentrations were similar to the values predicted by population PK modelling on the basis of a prediction-corrected visual predictive check, computed using the actual sampling time. In this interim safety analysis, 84.5% of patients had experienced adverse events of grade three or higher, the most common of which were hematologic and as expected. The results suggest that there is no clinically relevant PK DDI between carboplatin and trastuzumab. The safety profile of trastuzumab plus carboplatin and docetaxel was consistent with the known safety profile of this combination.

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.

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. The influence of demographic, laboratory, and disease characteristics on PK parameters was assessed. An exploratory exposure-response analysis compared various PK parameters at steady state with best overall tumor response and overall survival (OS).RESULTS:Trastuzumab PK was best described by a two-compartment model with parallel linear and nonlinear (Michaelis-Menten) elimination from the central compartment. Total clearance (and half-life) of trastuzumab was concentration-dependent. Body weight, prior gastrectomy, and serum albumin had the greatest influence on trastuzumab PK; increasing weight and decreasing albumin levels were associated with increased clearance, while prior gastrectomy correlated with decreased clearance. Median values for AUC, Cmax, and Cmin were lower in patients with progressive disease (PD) than other response categories, although the 1.5 interquartile ranges overlapped. Patients with the lowest Cmin had the highest PD rate and a shorter OS.CONCLUSIONS:In the advanced gastric cancer population, trastuzumab PK was best described by a two-compartment model with parallel linear and nonlinear elimination. Predicted PK exposure was lower than previously reported for breast cancer. Patients with the lowest Cmin had a shorter OS and the highest PD rate, but a distinct correlation was not observed for tumor response.

To characterize the population pharmacokinetics (PK) of pertuzumab across clinical trials in a variety of solid tumors, evaluate the potential impact of patient characteristics on PK, and confirm the appropriateness of the fixed (non-weight-based) dose.

BACKGROUND HannaH (NCT00950300) was a phase III, randomized, international, open-label study that compared pharmacokinetics (PK), efficacy, and safety of two different trastuzumab formulations [subcutaneous (s.c.) and intravenous (i.v.)] in HER2-positive, operable, locally advanced, or inflammatory breast cancer in the neoadjuvant/adjuvant setting. The co-primary end points, to show noninferiority of s.c. versus i.v. trastuzumab in terms of serum concentration (Ctrough) and pathologic complete response (pCR) were met; safety profiles were comparable at 12 months' median follow-up. Secondary end points included safety and tolerability, PK profile, immunogenicity, and event-free survival (EFS). We now report updated safety and efficacy data after a median follow-up of 20 months. PATIENTS AND METHODS Patients (N = 596) were treated with eight cycles of neoadjuvant chemotherapy, administered concurrently with 3-weekly s.c. trastuzumab (fixed dose of 600 mg) or the standard weight-based i.v. method. Following surgery, patients continued trastuzumab treatment to complete 1 year of therapy. Updated analyses of PK, efficacy, safety, and immunogenicity data were carried out. RESULTS s.c. trastuzumab was generally well tolerated and the incidence of adverse events (AEs), including grade 3 or 4 AEs, between treatment groups was comparable. A slightly higher incidence of serious AEs (SAEs), mainly due to infections, was reported with s.c. treatment {64 [21.5%; 95% confidence interval (CI) 17.0%-26.7%] versus 42 (14.1%; 95% CI 10.4%-18.6%) in the i.v. group}; however, the differences were small and often based on rare events, with no observable pattern across reported events. An early analysis of EFS showed rates of 95% in both groups 1 year postrandomization. Exploratory analyses did not reveal an association between toxicity and body weight or exposure. CONCLUSIONS Overall, the safety profile of s.c. trastuzumab was consistent with the previously published data from HannaH and the known safety profile of i.v. trastuzumab. EFS rates were comparable between the i.v. and s.c. groups. CLINICAL TRIAL NUMBER NCT00950300.