First-in-human phase I study of the bromodomain and extraterminal motif inhibitor BAY 1238097: emerging pharmacokinetic/pharmacodynamic relationship and early termination due to unexpected toxicity.

BACKGROUND: Bromodomain and extraterminal motif (BET) protein inhibition is a promising cancer treatment strategy, notably for targeting MYC- or BRD4-driven diseases. A first-in-human study investigated the safety, pharmacokinetics, maximum tolerated dose and recommended phase II dose of the BET inhibitor BAY 1238097 in patients with advanced malignancies. MATERIAL AND METHODS: In this phase I, open-label, non-randomised, multicentre study, patients with cytologically or histologically confirmed advanced refractory malignancies received oral BAY 1238097 twice weekly in 21-day cycles using an adaptive dose-escalation design at a starting dose of 10 mg/week. Model-based dose-response analysis was performed to guide dose escalation. Safety, pharmacokinetics, pharmacodynamics and tumour response were evaluated. RESULTS: Eight patients were enrolled at three dose levels (10 mg/week, n = 3; 40 mg/week, n = 3; 80 mg/week, n = 2). Both patients receiving 80 mg/week had dose-limiting toxicities (DLTs) (grade 3 vomiting, grade 3 headache and grade 2/3 back pain). The most common adverse events were nausea, vomiting, headache, back pain and fatigue. Pharmacokinetic analysis indicated a linear dose response with increasing dose. Two patients displayed prolonged stable disease; no responses were observed. Biomarker evaluation of MYC and HEXIM1 expression demonstrated an emerging pharmacokinetic/pharmacodynamic relationship, with a trend towards decreased MYC and increased HEXIM1 expression in response to treatment. CONCLUSION: The study was prematurely terminated because of the occurrence of DLTs at a dose below targeted drug exposure. Pharmacokinetic modelling indicated that an alternate dosing schedule whereby DLTs could be avoided while reaching efficacious exposure was not feasible. Registration number: NCT02369029.

Translational pharmacokinetic-pharmacodynamic modelling; application to cardiovascular safety data for PF-00821385, a novel HIV agent.

AIM: To assess the translation of pharmacokinetic-pharmacodynamic (PK-PD) relationships for heart rate effects of PF-00821385 in dog and man. METHODS: Cardiovascular telemetric parameters and concentration data were available for animals receiving active doses (0.5-120 mg kg(-1), n= 4) or vehicle. PF-00821385 was administered to 24 volunteers and pharmacokinetic and vital signs data were collected. PK-PD models were fitted using nonlinear mixed effects. RESULTS: Compartmental models with linear absorption and clearance were used to describe pharmacokinetic disposition in animal and man. Diurnal variation in heart and pulse rate was best described with a single cosine function in both dog and man. Canine and human heart rate change were described by a linear model with free drug slope 1.76 bpm microM(-1)[95% confidence interval (CI) 1.17, 2.35] in the dog and 0.76 bpm microM(-1) (95% CI 0.54, 1.14) in man. CONCLUSIONS: The preclinical translational of concentration-response has been described and the potential for further interspecies extrapolation and optimization of clinical trial design is addressed.

Improving the design and analysis of high-throughput screening technology comparison experiments using statistical modeling.

Contemporary small-molecule drug discovery frequently involves the screening of large compound files as a core activity. Subsequently cost, speed, and safety become critical issues. In order to meet this need, numerous technologies have been developed to allow mix and measure approaches, facilitate miniaturization, and to increase speed and to minimize the use of potentially hazardous reagents such as radioactive materials. However, despite the on-paper advantages of these new technologies, risks can remain undefined. For example, the question of whether the novel method will facilitate identification of active chemical series in a way that is comparable with conventional methods arises. In order to address this question, we have taken the approach of carrying out experiments to directly compare the output of high-throughput screens using a given novel approach and a traditional method. The concordance between the screening methods can then be determined via comparison of the numbers and structures of the active molecules identified. This article describes the approach taken in our laboratory to minimize variability in such experiments and shows data that exemplifies the general result of lower than expected concordance. Statistical modeling was subsequently used to facilitate this interpretation. The model used beta-distribution function to generate a real-activity frequency relationship with added normal random error and occasional outliers to represent assay variability. Hence, the effect of assay parameters such as the threshold, the number of real actives, and the number of outliers and the standard deviation could readily be explored. The model was found to describe the data reasonably and moreover was found to be of great utility when it came to planning further optimal experiments. A key conclusion from the model was that concordance between screening methods could appear poor even when one approach is compared with itself. This occurs simply because the result is a function of assay threshold, standard deviation and the true compound % activity. In response to this finding we have adopted alternative experimental designs that more reliably measure the concordance between screening methods.

NanoStore: a concept for logistical improvements of compound handling in high-throughput screening.

Small molecule screening, the systematic encounter of biology space with chemical space, has provoked the emergence of a whole industry that recreates itself by constant iterative improvements to this process. The authors describe an approach to tackle the problem for one of the most time-consuming steps in the execution of a screening campaign, namely, the reformatting of high-throughput screening test compounds from master plates to daughter assay plates used in the execution of the screen. Through an engineered storage procedure, they prepare plates ahead of the screening process with the respective compounds in a ready-to-use format. They show the biological inertness of the method and how it facilitates efficient recovery of compound activity. This uncoupling of normally interconnected processes provides time and compound savings, avoids repeated freeze-thaw cycles of compound solutions, and removes the problems associated with the DMSO sensitivity of certain assays types.