Immunogenicity, commonly manifested through the development of anti-drug antibodies (ADAs), is a critical concern for therapeutic antibodies as it can adversely affect pharmacokinetics (PK), efficacy, and safety. Althoug...Immunogenicity, commonly manifested through the development of anti-drug antibodies (ADAs), is a critical concern for therapeutic antibodies as it can adversely affect pharmacokinetics (PK), efficacy, and safety. Although ADA-related impacts have been closely evaluated for individual antibody drugs, cross-product analyses of approved antibody drugs remain limited. In this study, we examined 92 antibody therapeutics approved by the Japanese regulatory authority as of March 2024, focusing on their review reports and prescribing information, to quantitatively assess the actual clinical impacts of ADA. Among these drugs, ADA-related decreased drug exposure, reduced efficacy, and worsened safety were indicated in the prescribing information of 18.5%, 10.9%, and 5.4%, respectively. Interestingly, ADA-related descriptions of both decreased drug exposure and reduced efficacy were observed in significantly lower proportions among oncology drugs than among non-oncology drugs. Furthermore, humanized antibodies exhibited higher proportions of ADA-related impacts than human antibodies; in particular, decreased exposure was significantly more common with humanized antibodies (27.7%) than with human antibodies (8.6%), supporting the concept that human antibodies have lower immunogenic potential. In addition, our evaluation of review reports indicated that all drugs with ADA-related reduced efficacy had decreased exposure. To the best of our knowledge, this is the first study to quantitatively evaluate the clinical impact of immunogenicity in approved antibody therapeutics in Japan. These results are expected to inform the appropriate clinical use of antibody therapeutics and contribute to a more comprehensive understanding of immunogenicity risk assessments during clinical development.
Short contacts between medical devices and medications that they contain can cause drug sorption or leaching of unwanted compounds which can have clinical consequences. However, the parameters that govern these interacti...Short contacts between medical devices and medications that they contain can cause drug sorption or leaching of unwanted compounds which can have clinical consequences. However, the parameters that govern these interactions are still incompletely understood. The objectives of this study were to evaluate the impact of the formulation parameters on migration of 2,4 Di-tert-butylphenol (2,4 DTBP) and sorption of tacrolimus (TAC) in a model micellar ophthalmic drug formulation which is known to interact with silicone elastomers. A design of experiments was established to evaluate the impact of the formulation parameters on 2,4 DTBP leaching and tacrolimus sorption by varying the initial concentrations of TAC (0.04; 0.2 and 1 mg/mL), polyoxyethylenated castor oil (KEL) (32; 80 and 200 mg/mL) and ethanol absolute (EtOH) (10 and 100 mg/mL), at 5°C and 25°C, during static contact between various formulations and silicone valves obtained from an ophthalmic multidose delivery device. Concentrations of 2,4 DTBP and TAC were monitored by liquid chromatography coupled with an UV-visible detector. Under the conditions studied, the amount of 2,4 DTBP leaching out increased during contact with the silicone valve, with increasing TAC concentration being quite interestingly the main factor decreasing its ability to leach out, whilst ethanol increased its leachability. The silicone valve did not cause any significant decrease of TAC concentrations over the duration of the study, regardless of the concentrations of KEL, EtOH, or temperature. This study showed the impact of formulation on the leaching of 2,4 DTBP from a silicone component.
A special panel session at the 2024 NCS Conference in Wiesbaden, Germany, brought together experts to explore the evolving landscape of patient-centric drug product development and specifications. Traditional specificati...A special panel session at the 2024 NCS Conference in Wiesbaden, Germany, brought together experts to explore the evolving landscape of patient-centric drug product development and specifications. Traditional specifications often rely on manufacturing variability and phase 3 clinical trial data. However, patient-centric specifications shift the focus toward direct clinical relevance, establishing customer-driven acceptance criteria. Discussions covered innovative approaches to defining patient-centric specifications, leveraging prior knowledge, biopharmaceutics, formulation science, regulatory input, and statistical methodologies. The session also highlighted efficient QbD studies, enabling the linkage of Critical Process Parameters (CPPs) and Critical Material Attributes (CMAs) to Chemistry, Manufacturing and Controls (CMC) Critical Quality Attributes (CQAs). While these approaches hold great promise, challenges remain such as cross-disciplinary collaboration, data integration, and the development of robust databases to inform future drug and biologicals development. As industry experience grows, these efforts will pave the way for continuous improvement in nonclinical-clinical linkage designs, enhancing patient outcomes.
Chronic human immunodeficiency virus (HIV) infection continues to pose a major global health challenge, with an estimated 39.9 M cases and 1.3 M new infections per year. Up to 75%, of people with HIV (PWH) are currently...Chronic human immunodeficiency virus (HIV) infection continues to pose a major global health challenge, with an estimated 39.9 M cases and 1.3 M new infections per year. Up to 75%, of people with HIV (PWH) are currently being treated with antiretroviral therapy. The development of effective treatments for HIV requires a detailed understanding of the virus-host interaction. Often, mathematical models are used to inform this understanding as well as to characterize therapeutic response. This work aims to develop a single and fully identifiable population semi-mechanistic pharmacokinetic/pharmacodynamic (popPKPD) model integrating data (drug levels, CD4 + T cells and viral RNA) of five different antiretroviral (ARV) drugs administered in monotherapy: lenacapavir, bictegravir, tenofovir alafenamide, emtricitabine and elvitegravir. Data were obtained from six phase 1 clinical studies and model development was performed using NONMEM 7.5.1. The viral dynamics were best described by expanding the "basic" viral dynamics model with two more populations of infected cells: chronically and latently infected. Obtained death rates values of infected cells & virus were consistent with literature values. Population baseline HIV-RNA was estimated to be 43,460 copies/mL, with an IIV of 141%, the estimated baseline concentrations of CD4 + cells varied largely across the different cell types in the model: 410, 20, 7 and 7 cells/mL for uninfected, infected, chronic and latently infected cells, respectively. The popPKPD model was able to capture key aspects of viral dynamics, drug behaviour, and treatment response. The models developed will serve as a useful tool for further development and optimization of these HIV therapies, especially when evaluating multiple ARVs to be administered in a novel combination setting.
Formation of anti-drug antibodies (ADA) and, in particular, neutralizing antibodies (NAb), is a major risk to the development of biotherapeutics. Cell-based assays, which can reflect the mechanistic interactions among th...Formation of anti-drug antibodies (ADA) and, in particular, neutralizing antibodies (NAb), is a major risk to the development of biotherapeutics. Cell-based assays, which can reflect the mechanistic interactions among the drug, target, and NAb, are often most suitable for the detection of NAb. We report the development and validation of cell-based platform assays for a class of incretin molecules. An affinity capture elution step was employed to improve drug tolerance of a cell-based cyclic adenosine monophosphate (cAMP) assay. Assay conditions and procedures, including acid elution, cell density, and TAG labeled cAMP (cAMP-TAG) incubation time and concentration, were thoroughly optimized. Delta percent (Δ%) Neutralization was used to reduce assay variability during validation and sample analysis. This platform method has been applied to several incretin molecules and has demonstrated desired sensitivity, drug tolerance, and robustness.
Using pharmacometrics to inform drug discovery and development decisions requires effective communication of models and data to all stakeholders. The new "vachette" visualization method presented here enables modelers an...Using pharmacometrics to inform drug discovery and development decisions requires effective communication of models and data to all stakeholders. The new "vachette" visualization method presented here enables modelers and non-modelers to see how a model integrates and represents all data across relevant subgroups, showing how the model "sees" the data when it accounts for covariates. Vachette starts with user-provided model simulations ("curves"), together with observations used in creating (or otherwise relevant to) the model. It automatically produces a single, intuitive plot overlaying all observations onto a user-selected reference curve, accounting for covariate effects and preserving remaining random effects. The method automatically identifies characteristic landmarks (e.g., minima, maxima, and inflection points) which are used to split each curve into segments. A transformation on both x- and y-axes is then applied to each segment and its corresponding observations, accounting for covariate effects by aligning the segments to the reference, allowing intuitive visualization in one plot of covariate effects and of model fit to the data, preserving the distance between model predictions and the observations. Vachette-transformed data can also be used to enhance the utility of model assessments such as visual predictive checks and residual plots. Model visualizations using vachette enable easier and more effective evaluation and communication of the pharmacometric results critical to informing key decisions. Here the vachette method is described and its utility and flexibility are demonstrated through application to multiple types of pharmacometrics models, suggesting that vachette is a useful addition to the pharmacometrician's toolbox.
QSP models are increasingly being applied to drug development. Calibrating virtual populations (VPops) to clinical data helps explore patient variability, study populations of interest, and predict clinical outcomes for...QSP models are increasingly being applied to drug development. Calibrating virtual populations (VPops) to clinical data helps explore patient variability, study populations of interest, and predict clinical outcomes for new therapies. In previous work, we have developed the QSP Toolbox, a library of tools and workflows for developing VPops. The aim is to create a VPop that fits clinical data from a variety of sources and with a variety of data types, allowing for differences in the quality of the data. The goodness-of-fit (GOF) of the VPop is given by a scalar function whose form is inspired by the p-value of Fisher's combined hypothesis test. However, our VPop development workflow has been hampered by the need to perform repeated optimization of "prevalence weights" to maximize . In this article, we describe how we can speed up our workflow by using proxy GOF functions whose maximization can be reduced to the relatively easy problem of minimizing a convex quadratic objective function. A successful run of this "proxy-guided" workflow generates a VPop with very good -fit, but without having to continually maximize throughout the development process. We find that our proxy-guided workflow can calibrate VPops much faster than the original ( -guided) workflow.
Data integrity is necessary to help ensure the accuracy, consistency, validity and completeness of data. Data can be untraceably manipulated when it lacks adequate integrity. The FDA identified data integrity concerns wi...Data integrity is necessary to help ensure the accuracy, consistency, validity and completeness of data. Data can be untraceably manipulated when it lacks adequate integrity. The FDA identified data integrity concerns with the pharmacokinetic data of a bioequivalence (BE) study for rivaroxaban 20 mg tablets, which was conducted by a contract research organization (CRO) in support of an abbreviated new drug application (ANDA) submission. The hypothesis was that samples from the late cohort of the study might have been substituted or manipulated to allow an otherwise failing study to meet the BE endpoint. To test this hypothesis FDA investigators collected 2,392 plasma samples from the BE study at the CRO's clinical site. FDA laboratory then developed and validated a bioanalytical method and re-analyzed the BE study plasma samples. Comparison of the data generated by the CRO and FDA suggested that the study was manipulated by altering the volume of plasma samples used for bioanalysis. This manipulation was likely done to achieve a lower than actual maximum plasma concentration test/reference (C T/R) ratio.
Physiologically based pharmacokinetic (PBPK) modeling has emerged as a valuable tool in model-informed drug development (MIDD). This approach enables the integration of diverse experimental data to predict pharmacokineti...Physiologically based pharmacokinetic (PBPK) modeling has emerged as a valuable tool in model-informed drug development (MIDD). This approach enables the integration of diverse experimental data to predict pharmacokinetics (PK) and dosing regimens and facilitates understanding of mechanism of action (MoA) and pharmacodynamics (PD). In this article we provide a landscape analysis of PBPK submissions at the U.S. Food and Drug Administration, Center for Biologics Evaluation and Research (CBER). We summarize CBER's experience on PBPK modeling and simulation (M&S) for therapeutic proteins, cell and gene therapy products. We discuss specific case studies that illustrate the use of PBPK for dose selection of therapeutic proteins, highlight recent progress and provide our perspectives on potential application of PBPK for adeno-associated virus (AAV)-based gene therapies and messenger RNA (mRNA) therapeutics. For cell and gene therapy products, PBPK M&S is emerging as MIDD approaches to support clinical trial design, dose selection, predicting PK/PD, and facilitate quantitative understanding of safety and efficacy. As the field continues to evolve, PBPK modeling is well positioned to provide supportive evidence to facilitate the development of safe and effective biological products.
Recycling antibodies can enhance therapeutic efficacy by enabling efficient antigen removal through pH-dependent binding mechanisms enabling antibody recycling, but the optimal targets for this strategy remain unclear. T...Recycling antibodies can enhance therapeutic efficacy by enabling efficient antigen removal through pH-dependent binding mechanisms enabling antibody recycling, but the optimal targets for this strategy remain unclear. This work employs a mathematical modeling approach using a minimal PBPK model, along with global and local sensitivity analyses, to explore how target turnover rates influence the suitability of recycling antibodies. We applied this approach to a scenario featuring a soluble antigen with high baseline levels (1000 nM) that necessitates treatment with an antibody with a high intravenous dosing regimen. Our findings indicate that the recycling strategy is most effective for target antigens expressed at high levels, and particularly for those with half-lives of 10 to 30 h. In contrast, for antigens expressed at sufficiently low levels, where the antibody can be present in significant excess, further optimization of conventional antibodies to achieve higher antigen-binding affinity at neutral pH can be beneficial. While optimizing the off-rate at acidic pH is often the primary focus in the engineering of recycling antibodies, our analysis indicates that the on-rate at pH 6 is also an important parameter, albeit to a lesser extent. Therefore, the equilibrium dissociation constant (K) at pH 6 can be used as a composite parameter for effective design of recycling antibodies. For the soluble antigen embodied in the scenario described in this work, a pool of randomly selected antibodies, engineered to undergo recycling, reach half of their maximum antigen reduction capacity at a mean pH 6 K of 520 nM and 180 nM for targets with half-lives of 10 and 30 h, respectively.
Physiologically based pharmacokinetic (PBPK) models are commonly used in human drug discovery and development and human health risk assessment of environmental chemicals. One emerging application of PBPK models is to pre...Physiologically based pharmacokinetic (PBPK) models are commonly used in human drug discovery and development and human health risk assessment of environmental chemicals. One emerging application of PBPK models is to predict tissue residues and withdrawal times of drugs in food animals, which is important for human food safety assessment of animal-derived food products, such as meat, milk, and eggs. This review summarizes existing guidelines to establish the regulatory agency approved label withdrawal period and available pharmacometric methods to predict extralabel withdrawal times, with a focus on PBPK modeling. We conducted a comprehensive literature search on existing PBPK models in food animals. Two hundred thirteen PBPK models in different food animal species (e.g., cattle, swine, sheep, goats, and chickens) from 113 publications were identified. The general procedure to build a PBPK model for a drug in food animals to predict withdrawal times is summarized. Differences in PBPK modeling between humans and food animals and between different food animal species are discussed. Novel uses of PBPK models to predict extralabel withdrawal times are illustrated with recent case studies from the Food Animal Residue Avoidance Databank (FARAD). Recent advances and challenges in PBPK modeling in food animals are discussed, followed by our future perspectives on how to develop more robust PBPK models for food animals to address the safety assessment of animal-derived food products.
The current paradigm for detection of anti-drug antibodies (ADA) recommends a tiered strategy in which samples are tested in consecutive screening and confirmatory assays to ensure high sensitivity and specificity of det...The current paradigm for detection of anti-drug antibodies (ADA) recommends a tiered strategy in which samples are tested in consecutive screening and confirmatory assays to ensure high sensitivity and specificity of detection. In each tier individual responses are compared against a statistically determined cut point to make positive/negative classifications and advance the sample to the next testing tier. This manuscript argues that the idea of cut point is scientifically flawed and not suitable for making positive/negative ADA classifications. Cut point set at the ≥ 95th percentile of the population responses does not reduce the number of false negatives; on the contrary, it reduces the ability to detect ADA in 95% of the population with lower responses. Likewise, ADA classification of individual study samples should not be predicated by responses of other individuals used to determine the assay cut points. Experimental conditions used during cut point determination often differ from those encountered during testing of study samples (e.g. drug-naïve vs treated subjects, different disease state before and after treatment) and therefore a cut point may not be suitable for testing of post-baseline samples. Since cut point cannot be trusted to make ADA classifications, it is proposed to discard its use together with tiered testing and instead base the detection of ADA on post-baseline signal changes and their relationship to pharmacokinetics, pharmacodynamics, efficacy and safety. Discarding both cut point and tiered strategy is expected not only to significantly reduce the workload dedicated by bioanalytical laboratories to immunogenicity testing but also to improve data analysis and interpretation.
It is important to understand the key factors affecting the pharmacokinetics (PK), pharmacological response and toxicity of a drug to ensure clinical therapeutic efficacy and safety across disease populations. Traditiona...It is important to understand the key factors affecting the pharmacokinetics (PK), pharmacological response and toxicity of a drug to ensure clinical therapeutic efficacy and safety across disease populations. Traditionally, label dose-adjustment recommendations for patient populations are based on drug plasma concentrations. However, plasma PK may not be an appropriate surrogate for response and/or toxicity for drugs like statins with intracellular targets and tissue distribution influenced by membrane transporters. This study presents the integration of a physiologically-based pharmacokinetic model with a quantitative systems pharmacology and toxicology (PBPK-QSP-TOX) model for statins in patients with normal kidney function and in different stages of chronic kidney disease (CKD). The QSP model was informed by 2753 measurements of circulating LDL concentrations in 1147 patients (NCT00654537). The TOX model was informed by a meta-analysis of creatine kinase elevation incidence per statin dose in 30 clinical studies (49,284 patients). The CKD populations accounted for disease related changes to 1) anatomy and physiology, 2) drug enzymes and transporters expression and 3) lipoprotein metabolism. This study provides a qualified PBPK-QSP-TOX model for statins that accurately describe plasma concentration-time profiles, lipid-lowering effect and myotoxicity risk over investigated dose range for patients with normal kidney function and varying degree of CKD.
The efficient review and approval of chemistry, manufacturing and control (CMC) post-approval changes by global health authorities remains a critical aspect toward ensuring medical product commercial supply chains and pa...The efficient review and approval of chemistry, manufacturing and control (CMC) post-approval changes by global health authorities remains a critical aspect toward ensuring medical product commercial supply chains and patient access. The recent and growing implementation of innovative regulatory frameworks such as ICH Q12, large molecule statistical analysis of stability data, and global reliance has provided a positive impact on the health authority approval of CMC post-approval changes. This case study presents a large molecule multi-product post-approval change management protocol (PACMP) and the review/approval by a WHO-Listed Authority (WLA). The regulatory approval of this PACMP exemplifies how the principles of ICH Q12 combined with large molecule statistical stability analysis accelerates the implementation of a drug product aseptic filling line supporting the production of 5 globally approved products by 7 months. This accelerated approval by a WLA leads to the faster submission of the required approval letter/module 3 documentation to global national regulatory authorities leveraging WHO Good Reliance Procedures to improve rest-of-world regulatory review/approval timelines.
Generic ophthalmic drug product development is challenging, and innovative methodologies to complement traditional bioequivalence (BE) studies for BE assessment are desirable to promote their evaluation. Ocular physiolog...Generic ophthalmic drug product development is challenging, and innovative methodologies to complement traditional bioequivalence (BE) studies for BE assessment are desirable to promote their evaluation. Ocular physiologically based pharmacokinetic (PBPK) models can provide insight into drug partitioning in eye tissues that are too invasive to access in humans. An approach has been previously validated to translate ocular exposure from rabbits to humans for some ophthalmic solutions and suspensions. This study aims to demonstrate the utility of an ocular PBPK model to predict human exposure following the administration of ophthalmic ointment. Ofloxacin (OFL) ointment is presented as a case study. The Ocular Compartmental Absorption and Transit (OCAT™) model within GastroPlus® v9.9 was used to build a PBPK model for OFL ophthalmic solution and ointment that accounts for OFL release from the formulation into the tears and eye tissues where it is applied, ointment application time, ocular absorption, and distribution in the rabbit eye. The model was subsequently used to predict OFL exposure in humans after topical administration of solution or ointment. Drug and formulation-specific parameters were used as validated in the mode for rabbits. Physiological parameters were adjusted to match human ocular physiology. Simulated human ocular pharmacokinetic (PK) profiles were compared with the observed ocular tissue concentration data to assess the OCAT model's ability to predict human ocular exposure. The OCAT model for rabbits accurately described the observed concentrations in aqueous humor following the topical administration of OFL solution or ointment. For the ointment formulation, the Higuchi release rate and the application time of the formulation were fitted to describe the observed data. After adjustment of physiological parameters to represent the human eye, the predicted aqueous humor concentrations following ocular administration of OFL solution or ointment were within the range of observed values. More case studies for other ophthalmic ointment drug products will be needed to confirm this study's results. Nevertheless, the positive preclinical to clinical extrapolation for OFL represents an important step in the validation process of human exposure using an ocular PBPK model validated in the rabbit.
Bispecific antibodies (BsAbs) have emerged as a promising class of therapeutics to treat complex diseases, offering advantages in dual targeting simultaneously compared to monospecific antibodies. However, BsAbs often re...Bispecific antibodies (BsAbs) have emerged as a promising class of therapeutics to treat complex diseases, offering advantages in dual targeting simultaneously compared to monospecific antibodies. However, BsAbs often require advanced engineering, and the novel formats present challenges for the development of clinical anti-drug antibody (ADA) assays. Immunogenicity evaluation is a required study endpoint during the clinical development of biotherapeutics, and bridging immunoassay is a common method for developing clinical ADA assays. However, in two of our BsAb programs, the traditional bridging enzyme-linked immunosorbent assay (ELISA) was unable to detect surrogate ADAs directed against the arm containing multivalent domains. Further investigations revealed that the surrogate ADAs to the multivalent binding domain of the two BsAbs predominantly form 1:1 complexes with the drug, even in the presence of a significant excess of the BsAbs. To overcome the limitations of traditional bridging ELISA, we explored alternative assay approaches and developed fit-for-purpose ADA assays tailored to supporting multivalent BsAbs. Here, we present two case studies of multivalent BsAb analyzed using a stepwise ELISA format, where the drug is used for capture and a recombinant human high affinity Fc gamma receptor 1A (FcγRIa) is used for detection of the ADAs, leveraging the LALAPG attenuated effector function mutations present in both BsAbs. This work highlights the complexity of bioanalytical challenges in developing advanced therapeutic modalities and showcases the innovative solutions required to support the rapidly evolving field of BsAb therapeutics.
Minipig models are rapidly gaining popularity in gene therapy preclinical studies. This includes biodistribution studies that are required by regulatory agencies, but are poorly described in the literature. This is parti...Minipig models are rapidly gaining popularity in gene therapy preclinical studies. This includes biodistribution studies that are required by regulatory agencies, but are poorly described in the literature. This is particularly true for ddPCR assays with enhanced sensitivity over traditional "real-time" PCR. We, therefore, validated a novel duplex ddPCR assay for quantifying AVGN7, an AAV gene therapeutic featuring a codon-optimized human Smad7 gene and the porcine RPP30 reference gene, in Göttingen minipig tissues. The DNA extraction methods were optimized to ensure maximum recovery of target gene. Validation parameters included accuracy and precision, limit of detection, ruggedness/robustness, selectivity, recovery, dilutional linearity and stability. The assay was sensitive to 10 cp/µg gDNA while intra- and inter-accuracy and precision were demonstrated for the dynamic range of 25,000-5 cp/µL where the inter-assay total error was ≤ 35.5% for AVGN7 and ≤ 4.3% for RPP30. Moreover, ruggedness was assessed over time using multiple analysts, instruments and reagent lots, demonstrating high reliability and reproducibility. Linearity was established across 1,000-fold dilutions and stability after 6 freeze-thaw cycles and 24 h at room temperature. Selectivity was evaluated in unspiked and post-spiked samples using multiple lots of different tissue matrices. High recovery of AVGN7 during nucleic acid extraction was also demonstrated for all tissues. These data not only validate the assay for tracking and quantifying AVGN7 in preclinical studies with Göttingen minipigs, but additionally address challenges of using pig models in general while providing a procedural road map for developing other AAV biodistribution assays.