pharmacokinetic analysis of the oral thrombin inhibitor dabigatran etexilate in patients with non-valvular atrial fibrillation from the RE-LY trial.J Thromb Haemost 2011; 9: 2168-75.Summary. Background: Dabigatran etexilate (DE) is an orally absorbed prodrug of dabigatran, a thrombin inhibitor that exerts potent anticoagulant and antithrombotic activity. Objectives: To characterize the pharmacokinetics of dabigatran in patients with non-valvular atrial fibrillation (AF) from the Randomized Evaluation of Long-term Anticoagulant Therapy (RE-LY) trial and to quantify the effect of selected factors on pharmacokinetic (PK) model parameters. Patients and methods: A total of 27 706 dabigatran plasma concentrations from 9522 patients who received DE 110 or 150 mg twice daily were analyzed with non-linear mixed-effects modeling. Results: The pharmacokinetics of dabigatran were best described by a twocompartment disposition model with first-order absorption. The covariates creatinine clearance (CRCL), age, sex, heart failure and the ethnic subgroup ÔSouth AsianÕ exhibited statistically significant effects on apparent clearance of dabigatran. Body weight and hemoglobin significantly influenced the apparent volume of distribution of the central compartment. Concomitant medication with proton-pump inhibitors, amiodarone and verapamil significantly affected the bioavailability. However, all of the statistically significant factors that were identified, except for renal function status, showed only small to moderate effects (< 26% change in exposure at steady state). On the basis of simulations from the final population PK model, a dose of 75 mg twice daily would result in similar exposure for severely renally impaired patients with CRCL of 15-30 mL min )1 and patients with normal renal function receiving 150 mg twice daily. Conclusions: The analysis provides a thorough PK characterization of dabigatran in the AF patient population from RE-LY. None of the covariates investigated, with the exception of renal function, warrants dose adjustment.

Purpose: To assess safety, pharmacokinetics, maximum tolerated dose, and preliminary efficacy of bivatuzumab mertansine. Bivatuzumab is a humanized monoclonal antibody directed against CD44v6, which previously seemed to be safe in phase I radioimmunotherapy trials, whereas the conjugated mertansine is a potent maytansine derivative. Experimental Design: Patients with incurable squamous cell carcinoma of the head and neck or esophagus were eligible. Bivatuzumab was given weekly for 3 consecutive weeks by i.v. infusion. One patient was planned to be treated at each dose tier as long as toxicity did not reach grade 2; otherwise, three patients had to be treated until dose-limiting toxicity occurred. Starting dose was 20 mg/m 2 and dose was subsequently escalated in steps of 20 mg/m 2 . Patients without diseaseprogression and not experiencing dose-limiting toxicity were eligible for repeated courses. Blood serum samples were taken throughout the treatment period to determine the pharmacokinetic properties of bivatuzumab mertansine and to assess the human anti^bivatuzumab mertansine antibody response. Results: Seven patients received a total of 23 weekly doses of bivatuzumab mertansine. One patient at the 100 mg/m 2 and one at the 120 mg/m 2 level experienced stable disease during treatment phase but also developed grade 1skin toxicity (desquamation). One of them received a second treatment course. At the highest dose level achieved in this study (140 mg/m 2 ), one patient developed toxic epidermal necrolysis after two infusions and died. Massive apoptosis of skin keratinocytes had occurred, whereas only symptomatic therapy for skin toxicity was available. The riskbenefit assessment of all patients treated in the total phase I program (4 clinical trials, 70 patients) turned out to be negative after consideration of this case of a toxic epidermal necrolysis and the skin-related adverse events observed in the other trials.Therefore, development of the conjugate was discontinued. Interindividual variability in pharmacokinetic variables was low and exposure to BIWI 1 increased proportionally with dose. No anti^bivatuzumab mertansine reactions were observed. Conclusion: The main toxicity of bivatuzumab mertansine was directed against the skin, most probably due to CD44v6 expression in this tissue. The majority of skin reactions was reversible; however, one fatal drug-related adverse event had occurred. Clinical development was discontinued before reaching maximum tolerated dose.

This document was developed to enable greater consistency in the practice, application, and documentation of Model‐Informed Drug Discovery and Development (MID3) across the pharmaceutical industry. A collection of “good practice” recommendations are assembled here in order to minimize the heterogeneity in both the quality and content of MID3 implementation and documentation. The three major objectives of this white paper are to: i) inform company decision makers how the strategic integration of MID3 can benefit R&D efficiency; ii) provide MID3 analysts with sufficient material to enhance the planning, rigor, and consistency of the application of MID3; and iii) provide regulatory authorities with substrate to develop MID3 related and/or MID3 enabled guidelines.

Background Airway inflammation, mediated in part by LTB4, contributes to lung destruction in patients with cystic fibrosis (CF). LTB4-receptor inhibition may reduce airway inflammation. We report the results of a randomized, double-blind, placebo-controlled study of the efficacy and safety of the leukotriene B4 (LTB4)-receptor antagonist BIIL 284 BS in CF patients. Methods CF patients age ≥ 6 years with mild to moderate lung disease were randomized to oral BIIL 284 BS or placebo once daily for 24 weeks. Co-primary endpoints were change in FEV1 and incidence of pulmonary exacerbation. Results After 420 (155 children, 265 adults) of the planned 600 patients were randomized, the trial was terminated after a planned interim analysis revealed a significant increase in pulmonary related serious adverse events (SAE) in adults receiving BIIL 284 BS. Final analysis revealed SAEs in 36.1% of adults receiving BIIL 284 BS vs. 21.2% receiving placebo (p=0.007), and in 29.6% of children receiving BIIL 284 BS vs. 22.9% receiving placebo (p= 0.348). In adults, the incidence of protocol-defined pulmonary exacerbation was greater in those receiving BIIL 284 BS than in those receiving placebo (33.1% vs. 18.2% respectively; p=0.005). In children, the incidence of protocol-defined pulmonary exacerbation was 19.8% in the BIIL 284 BS arm, and 25.7% in the placebo arm (p=0.38). Conclusions While the cause of increased SAEs and exacerbations due to BIIL 284 BS is unknown, the outcome of this trial provides a cautionary tale for the administration of potent anti-inflammatory compounds to individuals with chronic infections, as the potential to significantly suppress the inflammatory response may increase the risk of infection-related adverse events.

Good practices around model‐informed drug discovery and development (MID3) aim to improve the implementation, standardization, and acceptance of these approaches within drug development and regulatory review. A survey targeted to clinical pharmacology and pharmacometric colleagues across industry, the US Food and Drug Administration (FDA), and the European Medicines Agency (EMA) was conducted to understand current and future roles of MID3. The documented standards were generally affirmed as a “good match” to current industry practice and regulatory expectations, with some identified gaps that are discussed. All have seen at least a “modest” step forward in MID3 implementation associated with greater organizational awareness and share the expectation for a future wider use and impact. The priority within organizations was identified as a limitation with respect to the future of MID3. Finally, potential solutions, including a global overarching MID3 regulatory guideline, to facilitate greater acceptance by industry and regulatory decision makers are discussed.

Abstract. During the last decades, the importance of modeling and simulation in clinical drug development, with the goal to qualitatively and quantitatively assess and understand mechanisms of pharmacokinetic processes, has strongly increased. However, this increase could not equally be observed for orally inhaled drugs. The objectives of this review are to understand the reasons for this gap and to demonstrate the opportunities that mathematical modeling of pharmacokinetics of orally inhaled drugs offers. To achieve these objectives, this review (i) discusses pulmonary physiological processes and their impact on the pharmacokinetics after drug inhalation, (ii) provides a comprehensive overview of published pharmacokinetic models, (iii) categorizes these models into physiologically based pharmacokinetic (PBPK) and (clinical data-derived) empirical models, (iv) explores both their (mechanistic) plausibility, and (v) addresses critical aspects of different pharmacometric approaches pertinent for drug inhalation. In summary, pulmonary deposition, dissolution, and absorption are highly complex processes and may represent the major challenge for modeling and simulation of PK after oral drug inhalation. Challenges in relating systemic pharmacokinetics with pulmonary efficacy may be another factor contributing to the limited number of existing pharmacokinetic models for orally inhaled drugs. Investigations comprising in vitro experiments, clinical studies, and more sophisticated mathematical approaches are considered to be necessary for elucidating these highly complex pulmonary processes. With this additional knowledge, the PBPK approach might gain additional attractiveness. Currently, (semi-)mechanistic modeling offers an alternative to generate and investigate hypotheses and to more mechanistically understand the pulmonary and systemic pharmacokinetics after oral drug inhalation including the impact of pulmonary diseases.

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Dabigatran, administered orally as the prodrug dabigatran etexilate (DE), is a direct thrombin inhibitor shown to be effective in the prevention of stroke and systemic embolism in patients with atrial fibrillation (AF). The aim of this analysis was to derive a modeling and simulation-based dose and dosing regimen for AF patients with severe renal failure who could potentially benefit from the use of DE. The exposure was simulated for AF patients with severe renal impairment for several combinations of doses (75, 110, 150 mg) and posologies (BID, QD, Q2D). Simulations were based on a population pharmacokinetic model derived from data from 9522 patients from the pivotal phase III study (RE-LY). Atrial fibrillation patients with a creatinine clearance (CRCL) of <30 to ≥15 mL/min treated with a dose of 75 mg DE BID have target plasma level and exposure data largely within the concentration range proven to be safe and effective in AF patients with CRCL >30 mL/min receiving 150 mg BID. This dosing algorithm was also confirmed and supported by the United States Food and Drug Administration Clinical Pharmacology Division using their model based on the data from the dedicated renal impairment study and taking into account the safety and efficacy information from RE-LY.