Human Dose and Pharmacokinetic Predictions for Biologics at Boehringer Ingelheim: A Retrospective Analysis.

INTRODUCTION: Accurate predictions of pharmacokinetics and efficacious doses for biologics in humans are critical for selecting appropriate first-in-human starting doses and dose ranges and for estimating clinical material needs and cost of goods. This also impacts clinical feasibility, particularly for subcutaneously administered biologics. METHODS: We performed a comprehensive comparison between predicted and observed clearances and doses in humans for a set of 22 biologic drugs developed at Boehringer Ingelheim (BI) over the last 2 decades. The analysis included biologics across three therapeutic areas comprising a wide variety of modalities: mono- and bispecific monoclonal antibodies (mAbs) and nanobodies and a Fab fragment. RESULTS: Our analysis showed that observed clearances in humans were within twofold of predicted clearances for 17 out of 20 biologics (85%). Six biologics had uncharacteristically high observed human clearances (range 32-280 mL/h) for their respective molecular classes, impacting their clinical developability. For three molecules, molecular characteristics contributed to the high clearance. Clinically selected doses were within twofold of predicted for 58% of projects. With 42% and 25% of projects selecting clinical doses higher than two- or threefold the predicted value, respectively, the importance of better understanding not only the pharmacokinetic (PK) but also the predictivity of pharmacodynamic models is highlighted. CONCLUSIONS: We provide a clinical pharmacology perspective on the commonly accepted twofold range of human clearance predictions as well as the implications of higher than predicted targeted efficacious plasma concentration on clinical development. Finally, an analysis of key success factors for biologics at BI was conducted, which may be relevant for the entire pharmaceutical industry. This is one of the largest retrospective analyses for biologics and provides further evidence that successful predictions of human PK and efficacious dose will be further facilitated by gathering key translational data early in research.

Using quantitative systems pharmacology modeling to optimize combination therapy of anti-PD-L1 checkpoint inhibitor and T cell engager.

Although immune checkpoint blockade therapies have shown evidence of clinical effectiveness in many types of cancer, the outcome of clinical trials shows that very few patients with colorectal cancer benefit from treatments with checkpoint inhibitors. Bispecific T cell engagers (TCEs) are gaining popularity because they can improve patients' immunological responses by promoting T cell activation. The possibility of combining TCEs with checkpoint inhibitors to increase tumor response and patient survival has been highlighted by preclinical and clinical outcomes. However, identifying predictive biomarkers and optimal dose regimens for individual patients to benefit from combination therapy remains one of the main challenges. In this article, we describe a modular quantitative systems pharmacology (QSP) platform for immuno-oncology that includes specific processes of immune-cancer cell interactions and was created based on published data on colorectal cancer. We generated a virtual patient cohort with the model to conduct in silico virtual clinical trials for combination therapy of a PD-L1 checkpoint inhibitor (atezolizumab) and a bispecific T cell engager (cibisatamab). Using the model calibrated against the clinical trials, we conducted several virtual clinical trials to compare various doses and schedules of administration for two drugs with the goal of therapy optimization. Moreover, we quantified the score of drug synergy for these two drugs to further study the role of the combination therapy.

Trends in industrialization of biotherapeutics: a survey of product characteristics of 89 antibody-based biotherapeutics.

There is considerable interest in the pharmaceutical industry toward development of antibody-based biotherapeutics because they can selectively bind diverse receptors and often possess desirable pharmacology. Here, we studied product characteristics of 89 marketed antibody-based biotherapeutics that were approved from 1986 to mid-2020 by gathering publicly available information. Our analyses revealed major trends in their emergence as the best-selling class of pharmaceuticals. Early on, most therapeutic monoclonal antibodies were developed to treat cancer, with CD20 being the most common target. Thanks to industrialization of antibody manufacturing technologies, their use has now blossomed to include 15 different therapeutic areas and nearly 60 targets, and the field is still growing! Drug manufacturers are solidifying their choices regarding types of antibodies and their molecular formats. IgG1 kappa continues to be the most common molecular format among marketed antibody-based biotherapeutics. Most antibody-based biotherapeutics approved since 2015 are either humanized or fully human, but the data we collected do not show a direct correlation between humanness and reported incidence of anti-drug antibodies. Furthermore, there have also been improvements in terms of drug product stability and high concentration liquid formulations suitable for subcutaneous route of administration, which are being approved more often in recent years. These improvements, however, have not been uniformly adopted across all therapeutic areas, suggesting that multiple options for drug product development are being used to serve diverse therapeutic purposes. Insights gained from this analysis may help us devise better end-to-end antibody-based biotherapeutic drug discovery and development strategies.

Analyze impact of tumor-associated kinetics on antibody delivery in solid tumors with a physiologically based pharmacokinetics/pharmacodynamics model.

Monoclonal antibody (mAb)-based drugs are critical anti-cancer therapies. Unfortunately, therapeutic efficacy can be compromised by spatially heterogeneous intratumoral Ab deposition. Binding-site barriers arising from Ab and tumor-associated kinetics often underlie this phenomenon. Quantitative insight into these issues may lead to more efficient drug delivery. Difficulties in addressing this issue include (1) lack of techniques to quantify critical kinetic events, (2) lack of a pharmacokinetic/pharmacodynamic (PK/PD) model to assess important parameters for specific tumor types, and (3) uncertainty or variability of critical kinetic factors even within a single tumor type. This study developed a mechanism-based PK/PD model to profile heterogeneous distribution of Ab within tumors and tested this model using real-life experimental data. Model simulations incorporating several uncertainties were used to determine how mAb and tumor-associated kinetics influence receptor occupancy. Simulations were also used to predict the potential impact of these findings in preclinical tumor models and human tumors. We found significant differences in tumor-associated kinetics between groups in which mAb therapy was effective versus groups in which it was ineffective. These kinetic differences included rates of tumor-associated antigen (TAA) degradation, TAA expression, apparent flow rates of interstitial fluid, and ratios of Ab-TAA complex internalization to TAA degradation. We found less significant differences in mAb kinetics, including rates of clearance or affinity for target antigens. In conclusion, our mechanism-based PK/PD model suggests that TAA-associated kinetic factors participate more significantly than those associated with the Ab in generating barriers to mAb delivery and distribution in tumors.

Where Did the Linker-Payload Go? A Quantitative Investigation on the Destination of the Released Linker-Payload from an Antibody-Drug Conjugate with a Maleimide Linker in Plasma.

The reactive thiol of cysteine is often used for coupling maleimide-containing linker-payloads to antibodies resulting in the generation of antibody drug conjugates (ADCs). Currently, a numbers of ADCs in drug development are made by coupling a linker-payload to native or engineered cysteine residues on the antibody. An ADC conjugated via hinge-cysteines to an auristatin payload was used as a model in this study to understand the impact of the maleimide linkers on ADC stability. The payload was conjugated to trastuzumab by a protease-cleavable linker, maleimido-caproyl-valine-citruline-p-amino-benzyloxy carbonyl (mcVC-PABC). In plasma stability assays, when the ADC (Trastuzumab-mcVC-PABC-Auristatin-0101) was incubated with plasma over a 144-h time-course, a discrepancy was observed between the measured released free payload concentration and the measured loss of drug-to-antibody ratio (DAR), as measured by liquid chromatography-mass spectrometry (LC-MS). We found that an enzymatic release of payload from ADC-depleted human plasma at 144 h was able to account for almost 100% of the DAR loss. Intact protein mass analysis showed that at the 144 h time point, the mass of the major protein in ADC-depleted human plasma had an additional 1347 Da over the native albumin extracted from human plasma, exactly matching the mass of the linker-payload. In addition, protein gel electrophoresis showed that there was only one enriched protein in the 144 h ADC-depleted and antipayload immunoprecipitated plasma sample, as compared to the 0 h plasma immunoprecipitated sample, and the mass of this enriched protein was slightly heavier than the mass of serum albumin. Furthermore, the albumin adduct was also identified in 96 h and 168 h postdose in vivo cynomolgus monkey plasma. These results strongly suggest that the majority of the deconjugated mc-VC-PABC-auristatin ultimately is transferred to serum albumin, forming a long-lived albumin-linker-payload adduct. To our knowledge, this is the first report quantitatively characterizing the extent of linker-payload transfer to serum albumin and the first clear example of in vivo formation of an albumin-linker-payload adduct.

Immune-mediated agranulocytosis caused by the cocaine adulterant levamisole: a case for reactive metabolite(s) involvement.

The United States Public Health Service Administration is alerting medical professionals that a substantial percentage of cocaine imported into the United States is adulterated with levamisole, a veterinary pharmaceutical that can cause blood cell disorders such as severe neutropenia and agranulocytosis. Levamisole was previously approved in combination with fluorouracil for the treatment of colon cancer; however, the drug was withdrawn from the U.S. market in 2000 because of the frequent occurrence of agranulocytosis. The detection of autoantibodies such as antithrombin (lupus anticoagulant) and an increased risk of agranulocytosis in patients carrying the human leukocyte antigen B27 genotype suggest that toxicity is immune-mediated. In this perspective, we provide an historical account of the levamisole/cocaine story as it first surfaced in 2008, including a succinct review of levamisole pharmacology, pharmacokinetics, and preclinical/clinical evidence for levamisole-induced agranulocytosis. Based on the available information on levamisole metabolism in humans, we propose that reactive metabolite formation is the rate-limiting step in the etiology of agranulocytosis associated with levamisole, in a manner similar to other drugs (e.g., propylthiouracil, methimazole, captopril, etc.) associated with blood dyscrasias. Finally, considering the toxicity associated with levamisole, we propose that the 2,3,5,6-tetrahydroimidazo[2,1-b]thiazole scaffold found in levamisole be categorized as a new structural alert, which is to be avoided in drug design.

Discovery of a (1H-benzoimidazol-2-yl)-1H-pyridin-2-one (BMS-536924) inhibitor of insulin-like growth factor I receptor kinase with in vivo antitumor activity.

Compound 3 (BMS-536924), a novel small-molecule inhibitor of the insulin-like growth factor receptor kinase with equal potency against the insulin receptor is described. The in vitro and in vivo biological activity of this interesting compound is also reported.

The discovery of BMS-275183: an orally efficacious novel taxane.

The evolution of 2, a C-4-methylcarbonate analogue of paclitaxel with minimal oral bioavailability and oral efficacy, into its C-3'-t-butyl-3'-N-t-butyloxycarbonyl analogue (15i), a novel taxane with oral efficacy in preclinical models that is comparable to iv administered paclitaxel, is described.