IMI - Oral biopharmaceutics tools project - Evaluation of bottom-up PBPK prediction success part 4: Prediction accuracy and software comparisons with improved data and modelling strategies.

Oral drug absorption is a complex process depending on many factors, including the physicochemical properties of the drug, formulation characteristics and their interplay with gastrointestinal physiology and biology. Physiological-based pharmacokinetic (PBPK) models integrate all available information on gastro-intestinal system with drug and formulation data to predict oral drug absorption. The latter together with in vitro-in vivo extrapolation and other preclinical data on drug disposition can be used to predict plasma concentration-time profiles in silico. Despite recent successes of PBPK in many areas of drug development, an improvement in their utility for evaluating oral absorption is much needed. Current status of predictive performance, within the confinement of commonly available in vitro data on drugs and formulations alongside systems information, were tested using 3 PBPK software packages (GI-Sim (ver.4.1), Simcyp® Simulator (ver.15.0.86.0), and GastroPlus™ (ver.9.0.00xx)). This was part of the Innovative Medicines Initiative (IMI) Oral Biopharmaceutics Tools (OrBiTo) project. Fifty eight active pharmaceutical ingredients (APIs) were qualified from the OrBiTo database to be part of the investigation based on a priori set criteria on availability of minimum necessary information to allow modelling exercise. The set entailed over 200 human clinical studies with over 700 study arms. These were simulated using input parameters which had been harmonised by a panel of experts across different software packages prior to conduct of any simulation. Overall prediction performance and software packages comparison were evaluated based on performance indicators (Fold error (FE), Average fold error (AFE) and absolute average fold error (AAFE)) of pharmacokinetic (PK) parameters. On average, PK parameters (Area Under the Concentration-time curve (AUC0-tlast), Maximal concentration (Cmax), half-life (t1/2)) were predicted with AFE values between 1.11 and 1.97. Variability in FEs of these PK parameters was relatively high with AAFE values ranging from 2.08 to 2.74. Around half of the simulations were within the 2-fold error for AUC0-tlast and around 90% of the simulations were within 10-fold error for AUC0-tlast. Oral bioavailability (Foral) predictions, which were limited to 19 APIs having intravenous (i.v.) human data, showed AFE and AAFE of values 1.37 and 1.75 respectively. Across different APIs, AFE of AUC0-tlast predictions were between 0.22 and 22.76 with 70% of the APIs showing an AFE > 1. When compared across different formulations and routes of administration, AUC0-tlast for oral controlled release and i.v. administration were better predicted than that for oral immediate release formulations. Average predictive performance did not clearly differ between software packages but some APIs showed a high level of variability in predictive performance across different software packages. This variability could be related to several factors such as compound specific properties, the quality and availability of information, and errors in scaling from in vitro and preclinical in vivo data to human in vivo behaviour which will be explored further. Results were compared with previous similar exercise when the input data selection was carried by the modeller rather than a panel of experts on each in vitro test. Overall, average predictive performance was increased as reflected in smaller AAFE value of 2.8 as compared to AAFE value of 3.8 in case of previous exercise.

[Implementation of the Latest Scientific Knowledge/Technologies and Activities for International Harmonisation of the Japanese Pharmacopoeia].

The Japanese Pharmacopoeia (JP) is an official document that defines the specifications, criteria, and standard test methods necessary to properly ensure the quality of medicines in Japan. To ensure the efficacy and safety of pharmaceutical products, it is essential to establish standards that ensure their quality. For this purpose, the JP aims to include all drugs that are important from the viewpoint of healthcare and medical treatment, and description of each monograph of medicine is maintained and improved so that those standards can be generally practiced. In addition, to play a key role as the official document in the field of pharmaceutical product quality, JP contents are enhanced by proactively introducing the latest scientific knowledge and technologies. As the international manufacturing of pharmaceutical products and their raw materials that are distributed in Japan is increasing, the JP has recently begun to promote the international harmonisation of pharmaceutical excipients and general tests through the Pharmacopoeial Discussion Group (PDG) and to swiftly implement the harmonised items in the JP. In addition, the JP will implement internationally harmonised concepts and specifications for pharmaceutical products, e.g., the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), to define the latest concepts of quality control for pharmaceutical products in the official document. We introduce the implementation of the latest scientific knowledge, technologies, and activities for international harmonisation of the JP.

Biowaiver Applications in Support of a Polymorph During Late-Stage Clinical Development of Verubecestat-Current Challenges and Future Opportunities for Global Regulatory Alignment.

Dissolution experiments to support an active pharmaceutical ingredient (API) form change in Verubecestat immediate release tablets were performed following current regulatory guidance published by health authorities in Canada, Australia, Japan, the EU, and the USA. Verubecestat API meets the requirements of a Biopharmaceutics Classification System class 1 compound and tablets are very  rapidly dissolving in aqueous dissolution media. While the in vitro data were reviewed favorably by these agencies, the divergence in regulatory requirements led to unnecessary work and highlights several issues companies operating globally face to justify product changes that have very little impact on quality. The data presented in this manuscript provide a compelling case for adjustments to the current draft ICH M9 guidance which provides recommendations for biowaiver applications. Specifically, this manuscript contains recommendations with respect to API attributes, selection of dissolution media and apparatus, and methods to assess dissolution similarity if needed, which should be considered for inclusion in a science- and risk-based global guidance document to benefit patients, regulators, and the pharmaceutical industry.

The Discriminatory Power of the BCS-Based Biowaiver: A Retrospective With Focus on Essential Medicines.

This article summarizes historic developments, recent expert opinions, and (currently) unresolved challenges concerning the Biopharmaceutics Classification System (BCS)-based Biowaiver. An overview of approval statistics and application potential, case examples addressing the discriminatory power of the procedure, as well as an outlook on possible refinements in the future are provided and critically discussed. Over the last decade, regulatory guidance documents have been harmonized, for example, following scientific consent on allowing biowaivers for BCS class III drugs, making over 50% of orally administered drugs on the World Health Organization Essential Medicines List eligible for an abbreviated approval. Biowaiver monographs that present a complete risk-benefit evaluation for individual drugs have been issued by the International Pharmaceutical Federation for more than 25% of those drugs with the long-range aim of covering all essential drugs. Unresolved issues that have emerged from reported examples of false-negative and false-positive outcomes in the literature demand further adjustments to the regulatory requirements. Possible solutions for resolving these issues are the use of modeling and simulation and refined biorelevant in vitro tests that are better able to discriminate between dosage forms with unequal performance in vivo, potentially allowing biowaivers for selected BCS II drugs.

Quality Risk Management Competency Model-Case for the Need for QRM Competencies.

The Pharmaceutical Regulatory Science Team (PRST), a research team based at the Dublin Technological University (TU Dublin) in Ireland, recently conducted a Quality Risk Management (QRM) survey and a face-to-face focus group workshop to assess the level of formality of QRM roles in the biopharmaceutical sector. This was carried out as part of a research study, which identified the need for the development of QRM role-based competencies as fundamental to realizing QRM's benefits. The research study followed a hybrid Delphi research methodology composed of: (1) Survey 1, (2) focus group workshop, (3) Survey 2, and (4) competency model development. This paper presents the results of Survey 1 and the focus group workshop. Survey 1 explored the need for QRM role-based competencies and the subsequent face-to-face focus group workshop built on this to propose initial standard QRM roles, with a view to confirming these and developing associated competencies. This paper presents the findings from Survey 1 and the focus group workshop. The results of the follow-up research activities will be presented in a subsequent paper.LAY ABSTRACT: The publication of the ICH Q9 Quality Risk Management (QRM) guideline in 2005 has greatly impacted the biopharmaceutical sector. Fourteen years after Q9, the benefits of QRM are yet to be realized. The biopharmaceutical sector still struggles with the implementation of Q9 principles to effectively assess and manage product quality risks as a surrogate for patient safety.This paper looks at the need for standard QRM roles and the associated competencies for those roles.

Dissolution and Translational Modeling Strategies Toward Establishing an In Vitro-In Vivo Link-a Workshop Summary Report.

This publication summarizes the proceedings of day 2 of a 3-day workshop on "Dissolution and Translational Modeling Strategies Enabling Patient-Centric Product Development." Patient-centric drug product development from a drug product quality perspective necessitates the establishment of clinically relevant drug product specifications via an in vitro-in vivo link. Modeling and simulation offer a path to establish this link; in this regard, physiologically based modeling has been implemented successfully to support regulatory decision-making and drug product labeling. In this manuscript, case studies of physiologically based biopharmaceutics modeling (PBBM) applied to drug product quality are presented and summarized. These case studies exemplify a possible path to achieve an in vitro-in vivo link and encompass (a) development of biopredictive dissolution methods to support biowaivers, (b) model-informed formulation selection, (c) predicting clinical formulation performance, and (d) defining a safe space for regulatory flexibility via virtual bioequivalence (BE). Workflows for the development and verification of absorption models/PBBM and for the establishment of a safe space using dissolution as an input are described with examples. Breakout session discussions on topics, such as current challenges and some best practices in model development and verification, are included as part of the Supplementary material.

Enabling Robust and Rapid Raw Material Identification and Release by Handheld Raman Spectroscopy.

A fast, reproducible, non-destructive method to confirm raw material identification in real-time upon material receipt within a warehouse environment is desired. Current practices in pharmaceutical manufacturing often employ compendia methods for raw material identification tests, which require sample preparation prior to time-consuming chemical analysis and often employ subjective spectral comparisons. We have developed, qualified, and validated a rapid objective identity method ("Rapid ID") by Raman spectroscopy using the Bruker BRAVO handheld Raman spectrometer for 46 common raw materials used in upstream and downstream biopharmaceutical cell culture-based processes. Materials in the Raman identification library include amino acids and other solid neat organic chemicals, liquid organics, polyatomic salts, polymers, emulsifiers, peptides, aqueous solutions, and buffers. Selection of reference spectra and hit quality index limit(s) was based upon a comprehensive spectral survey across multiple suppliers and lots to account for normal cause spectral variation. Method repeatability and reproducibility, selectivity, and robustness against various operational and environmental factors (e.g., instrumental variance, material packaging, and thermal effects) were evaluated. Benefits of a handheld Raman Rapid ID approach include significant reduction of the time for raw material quality release from weeks to minutes, enhanced objectivity, and robust data integrity via autonomous electronic reporting. In addition, routine collection of rich spectroscopic data on raw materials can be leveraged to support further continuous improvement initiatives, including routine monitoring of method performance, continuous improvement of the library, proactive detection of shifts in raw material properties, and provision of data for investigations focused on raw materials. Rapid ID methods are consistent with the move toward the principles of Pharma 4.0-high automated processes with continuous process verification and a holistic control strategy.LAY ABSTRACT: A fast, reproducible, non-destructive method is desired to confirm raw material identification in real time upon receipt within a warehouse environment. We have developed, qualified and validated a rapid objective identity method ("Rapid ID") by Raman spectroscopy using the Bruker BRAVO handheld Raman spectrometer for 46 common raw materials used in upstream and downstream biopharmaceutical cell culture-based processes. Benefits of a handheld Raman Rapid ID approach include significant time reduction of raw material quality release from weeks to minutes, enhanced objectivity, and robust data integrity via autonomous electronic reporting. Rapid ID methods are consistent with the move toward the principles of Pharma 4.0: high automated processes with continuous process verification and a holistic control strategy.

What Does It Really Look Like to Properly Address a "Human Error Problem" in Biopharma? The Human Performance Blue-Sky Description That Will Help Improve Industry Performance.

A clear picture of what Human Performance success looks like is now available from BioPhorum, where members of the Human Performance workstream have defined a blue-sky for the industry. This blue-sky document is both a guide and an assessment tool, which includes warning flags that help to identify significant obstacles in the way of effective human performance integration with operations that must be addressed. The effort to improve reliable operations within biopharma using elements of human performance borrowed from other industries have experienced uneven results and slow progress across the last seven years and has been bogged down for multiple significant reasons. These include a mental model that persists within the industry where workers are assumed to be the problem that needs fixing, the mistaken belief that Lean/Operational Excellence is a cure-all and nearly equivalent to human performance, neglecting the need to fundamentally rethink why and how investigations are performed, and truly underestimating the time, effort, strength of sponsor support, and strategy needed to change how work is designed, executed, and then later learned from.LAY ABSTRACT: Human Performance is an integrated risk management approach to improving systems, that includes human factors and systems safety, that leads to higher reliability and enhanced operational resilience. A clear picture of what Human Performance looks like in biopharma is available from the BioPhorum, where members of the Human Performance workstream have defined a blue-sky for the industry. This blue-sky document is both a guide and an assessment tool that will help to identify the steps to effective human performance integration with operations. The effort to improve reliable operations within biopharma using elements of human performance borrowed from other industries has experienced uneven results and slow progress across the last seven years and has been bogged down for multiple significant reasons. These include a mental model that persists within the industry where workers are assumed to be the problem that needs fixing, the mistaken belief that Lean practices (intended to improve productivity & efficiency) is a cure-all and nearly equivalent to human performance, neglecting the need to fundamentally rethink why and how investigations are performed, and truly underestimating the time, effort, strength of sponsor support needed to change how work is designed, executed, and then later learned from.

The first World Health Organization International Standard for infliximab products: A step towards maintaining harmonized biological activity.

Due to the increase in the number of infliximab products, the need for global harmonization of the bioactivity of this monoclonal antibody was recognized by the World Health Organization (WHO). In response, the National Institute for Biological Standards and Control (NIBSC) developed the first international standard (IS) for infliximab, which targets tumour necrosis factor (TNF). Each ampoule is assigned values of 500 IU of TNF neutralizing activity and 500 IU of binding activity. Two preparations of infliximab were formulated and lyophilized at NIBSC prior to evaluation in a collaborative study for their suitability to serve as an IS for the in vitro biological activity of infliximab. The study involved participants using in vitro cell-based bioassays (TNF neutralization, antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity) and binding assays. The results of this study showed that the candidate preparation, coded 16/170, is suitable as an IS for infliximab bioactivity. This infliximab IS from NIBSC, is intended to support in vitro bioassay calibration and validation by defining international units of bioactivity. The proposed unitages, however, are not intended to revise product labelling or dosing requirements, as any decisions regarding this relies solely with the regulatory authorities. Furthermore, the infliximab IS is not intended for determining the specific activity of products, nor to serve any regulatory role in defining biosimilarity. We briefly discuss the future use of WHO international standards in supporting the global harmonisation of biosimilar infliximab products.

Recommendations for Comparison of Productivity Between Fed-Batch and Perfusion Processes.

Due to the growing interest in integrated continuous processing in the biopharmaceutical industry, productivity comparison of batch-based and continuous processes is considered a challenge. Integrated continuous manufacturing of biopharmaceuticals requires scientists and engineers to collaborate effectively. Differing definitions, for example, of volumetric productivity, may cause confusion in this interdisciplinary field. Therefore, the aim of this communication is to reiterate the standard definitions and their underlying assumptions. Applying them to an exemplary model scenario allows to demonstrate the differences and to develop recommendations for the comparison of productivity of different upstream processes.

Enabling adoption of 2D-NMR for the higher order structure assessment of monoclonal antibody therapeutics.

The increased interest in using monoclonal antibodies (mAbs) as a platform for biopharmaceuticals has led to the need for new analytical techniques that can precisely assess physicochemical properties of these large and very complex drugs for the purpose of correctly identifying quality attributes (QA). One QA, higher order structure (HOS), is unique to biopharmaceuticals and essential for establishing consistency in biopharmaceutical manufacturing, detecting process-related variations from manufacturing changes and establishing comparability between biologic products. To address this measurement challenge, two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) methods were introduced that allow for the precise atomic-level comparison of the HOS between two proteins, including mAbs. Here, an inter-laboratory comparison involving 26 industrial, government and academic laboratories worldwide was performed as a benchmark using the NISTmAb, from the National Institute of Standards and Technology (NIST), to facilitate the translation of the 2D-NMR method into routine use for biopharmaceutical product development. Two-dimensional 1H,15N and 1H,13C NMR spectra were acquired with harmonized experimental protocols on the unlabeled Fab domain and a uniformly enriched-15N, 20%-13C-enriched system suitability sample derived from the NISTmAb. Chemometric analyses from over 400 spectral maps acquired on 39 different NMR spectrometers ranging from 500 MHz to 900 MHz demonstrate spectral fingerprints that are fit-for-purpose for the assessment of HOS. The 2D-NMR method is shown to provide the measurement reliability needed to move the technique from an emerging technology to a harmonized, routine measurement that can be generally applied with great confidence to high precision assessments of the HOS of mAb-based biotherapeutics.

Polymorphic and Quantum Chemistry Characterization of Candesartan Cilexetil: Importance for the Correct Drug Classification According to Biopharmaceutics Classification System.

The recommended method for the biopharmaceutical evaluation of drug solubility is the shake flask; however, there are discrepancies reported about the solubility of certain compounds measured with this method, one of them is candesartan cilexetil. The present work aimed to elucidate the solubility of candesartan cilexetil by associating others assays such as stability determination, polymorphic characterization and in silico calculations of intrinsic solubility, ionized species, and electronic structures using quantum chemistry descriptors (frontier molecular orbitals and Fukui functions). For the complete biopharmaceutical classification, we also reviewed the permeability data available. The polymorphic form used was previously identified as the form I of candesartan cilexetil. The solubility was evaluated in biorelevant media in the pH range of 1.2-6.8 at 37.0°C according to the stability previously assessed. The solubility of candesartan cilexetil is pH dependent and the dose/solubility ratios obtained demonstrated the low solubility of the prodrug. The in silico calculations supported the found results and evidenced the main groups involved in the solvation, benzimidazole, and tetrazol-biphenyl. The human absolute bioavailability reported demonstrates that candesartan cilexetil has low permeability and when associated with the low solubility allows to classify it as class 4 of the Biopharmaceutics Classification System.

Impact of the US FDA "Biopharmaceutics Classification System" (BCS) Guidance on Global Drug Development.

The FDA guidance on application of the biopharmaceutics classification system (BCS) for waiver of in vivo bioequivalence (BE) studies was issued in August 2000. Since then, this guidance has created worldwide interest among biopharmaceutical scientists in regulatory agencies, academia, and industry toward its implementation and further expansion. This article describes how the review implementation of this guidance was undertaken at the FDA and results of these efforts over last dozen years or so across the new, and the generic, drug domains are provided. Results show that greater than 160 applications were approved, or tentatively approved, based on the BCS approach across multiple therapeutic areas; an additional significant finding was that at least 50% of these approvals were in the central nervous system (CNS) area. These findings indicate a robust utilization of the BCS approach toward reducing unnecessary in vivo BE studies and speeding up availability of high quality pharmaceutical products. The article concludes with a look at the adoption of this framework by regulatory and health policy organizations across the globe, and FDA's current thinking on areas of improvement of this guidance.

A system identification approach for developing model predictive controllers of antibody quality attributes in cell culture processes.

As the biopharmaceutical industry evolves to include more diverse protein formats and processes, more robust control of Critical Quality Attributes (CQAs) is needed to maintain processing flexibility without compromising quality. Active control of CQAs has been demonstrated using model predictive control techniques, which allow development of processes which are robust against disturbances associated with raw material variability and other potentially flexible operating conditions. Wide adoption of model predictive control in biopharmaceutical cell culture processes has been hampered, however, in part due to the large amount of data and expertise required to make a predictive model of controlled CQAs, a requirement for model predictive control. Here we developed a highly automated, perfusion apparatus to systematically and efficiently generate predictive models using application of system identification approaches. We successfully created a predictive model of %galactosylation using data obtained by manipulating galactose concentration in the perfusion apparatus in serialized step change experiments. We then demonstrated the use of the model in a model predictive controller in a simulated control scenario to successfully achieve a %galactosylation set point in a simulated fed-batch culture. The automated model identification approach demonstrated here can potentially be generalized to many CQAs, and could be a more efficient, faster, and highly automated alternative to batch experiments for developing predictive models in cell culture processes, and allow the wider adoption of model predictive control in biopharmaceutical processes. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 33:1647-1661, 2017.

Recent Topics of Research in the Characterization and Quality Control of Biopharmaceuticals in Japan.

The research and development of next-generation innovative medicines is a prominent interest of both the government and industries in Japan. On June 29, 2017, a kickoff meeting of a new research group focused on the quality issues of biopharmaceuticals was held in Tokyo with Prof. John Carpenter as an invited guest. The group's research focuses mainly on the evaluation and control of protein aggregates/subvisible particles in drug products, but the research topics also include glycan analysis, host-cell protein evaluation, bioassay validation, and analytical quality by design. The purpose of the group's activities is to resolve the critical and fundamental quality issues important to pharmaceutical companies through the collaboration of industries, academia, and regulatory agencies. In this commentary, our current plan to address these issues and the discussion at the kickoff meeting are described.

Validation of Dissolution Testing with Biorelevant Media: An OrBiTo Study.

Dissolution testing with biorelevant media has become widespread in the pharmaceutical industry as a means of better understanding how drugs and formulations behave in the gastrointestinal tract. Until now, however, there have been few attempts to gauge the reproducibility of results obtained with these methods. The aim of this study was to determine the interlaboratory reproducibility of biorelevant dissolution testing, using the paddle apparatus (USP 2). Thirteen industrial and three academic laboratories participated in this study. All laboratories were provided with standard protocols for running the tests: dissolution in FaSSGF to simulate release in the stomach, dissolution in a single intestinal medium, FaSSIF, to simulate release in the small intestine, and a "transfer" (two-stage) protocol to simulate the concentration profile when conditions are changed from the gastric to the intestinal environment. The test products chosen were commercially available ibuprofen tablets and zafirlukast tablets. The biorelevant dissolution tests showed a high degree of reproducibility among the participating laboratories, even though several different batches of the commercially available medium preparation powder were used. Likewise, results were almost identicalbetween the commercial biorelevant media and those produced in-house. Comparing results to previous ring studies, including those performed with USP calibrator tablets or commercially available pharmaceutical products in a single medium, the results for the biorelevant studies were highly reproducible on an interlaboratory basis. Interlaboratory reproducibility with the two-stage test was also acceptable, although the variability was somewhat greater than with the single medium tests. Biorelevant dissolution testing is highly reproducible among laboratories and can be relied upon for cross-laboratory comparisons.

Opportunities and challenges of real-time release testing in biopharmaceutical manufacturing.

Real-time release testing (RTRT) is defined as "the ability to evaluate and ensure the quality of in-process and/or final drug product based on process data, which typically includes a valid combination of measured material attributes and process controls" (ICH Q8[R2]). This article discusses sensors (process analytical technology, PAT) and control strategies that enable RTRT for the spectrum of critical quality attributes (CQAs) in biopharmaceutical manufacturing. Case studies from the small-molecule and biologic pharmaceutical industry are described to demonstrate how RTRT can be facilitated by integrated manufacturing and multivariable control strategies to ensure the quality of products. RTRT can enable increased assurance of product safety, efficacy, and quality-with improved productivity including faster release and potentially decreased costs-all of which improve the value to patients. To implement a complete RTRT solution, biologic drug manufacturers need to consider the special attributes of their industry, particularly sterility and the measurement of viral and microbial contamination. Continued advances in on-line and in-line sensor technologies are key for the biopharmaceutical manufacturing industry to achieve the potential of RTRT. Related article: http://onlinelibrary.wiley.com/doi/10.1002/bit.26378/full.

Immunoassays for Measuring Serum Concentrations of Monoclonal Antibodies and Anti-biopharmaceutical Antibodies in Patients.

Monoclonal antibodies (mAbs) may be used as biopharmaceuticals to treat various diseases, ranging from oncology to inflammatory and cardiovascular affections. Trustworthy analytical methods are necessary to study their pharmacokinetics, both during their development and in post-marketing studies. Because biopharmaceuticals are macromolecules, ligand-binding assays (both immunoassays and bioassays) are methods of choice to measure their concentrations. Immunoassays are based on the capture of biopharmaceuticals by their target, which may be a circulating or membrane antigen or by an antibody recognizing their structure. Bioassays measure the activity of the biopharmaceutical in a specific in vitro test. A number of techniques have been reported, but their limits of detection and quantification vary widely. Anti-drug antibodies (ADA) against biopharmaceuticals are often formed and sometimes interfere with clinical efficacy. Accurate and reliable detection of ADA is therefore necessary. Binding of ADA is dependent on affinity and avidity, which makes quantification challenging. In this review, we discuss the benefits and limitations of each method to determine mAb levels and carefully compare ADA assays.

Throughput Optimization of Continuous Biopharmaceutical Manufacturing Facilities.

In order to operate profitably under different product demand scenarios, biopharmaceutical companies must design their facilities with mass output flexibility in mind. Traditional biologics manufacturing technologies pose operational challenges in this regard due to their high costs and slow equipment turnaround times, restricting the types of products and mass quantities that can be processed. Modern plant design, however, has facilitated the development of lean and efficient bioprocessing facilities through footprint reduction and adoption of disposable and continuous manufacturing technologies. These development efforts have proven to be crucial in seeking to drastically reduce the high costs typically associated with the manufacturing of recombinant proteins. In this work, mathematical modeling is used to optimize annual production schedules for a single-product commercial facility operating with a continuous upstream and discrete batch downstream platform. Utilizing cell culture duration and volumetric productivity as process variables in the model, and annual plant throughput as the optimization objective, 3-D surface plots are created to understand the effect of process and facility design on expected mass output. The model shows that once a plant has been fully debottlenecked it is capable of processing well over a metric ton of product per year. Moreover, the analysis helped to uncover a major limiting constraint on plant performance, the stability of the neutralized viral inactivated pool, which may indicate that this should be a focus of attention during future process development efforts.LAY ABSTRACT: Biopharmaceutical process modeling can be used to design and optimize manufacturing facilities and help companies achieve a predetermined set of goals. One way to perform optimization is by making the most efficient use of process equipment in order to minimize the expenditure of capital, labor and plant resources. To that end, this paper introduces a novel mathematical algorithm used to determine the most optimal equipment scheduling configuration that maximizes the mass output for a facility producing a single product. The paper also illustrates how different scheduling arrangements can have a profound impact on the availability of plant resources, and identifies limiting constraints on the plant design. In addition, simulation data is presented using visualization techniques that aid in the interpretation of the scientific concepts discussed.