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Sun Y, Yu X, Wang X, Yuan K, Wang G, Hu L, Zhang G, Pei W, Wang L, Sun C, Yang P. Bispecific antibodies in cancer therapy: Target selection and regulatory requirements. Acta Pharm Sin B 2023; 13:3583-3597. [PMID: 37719370 PMCID: PMC10501874 DOI: 10.1016/j.apsb.2023.05.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/25/2023] [Accepted: 05/06/2023] [Indexed: 09/19/2023] Open
Abstract
In recent years, the development of bispecific antibodies (bsAbs) has been rapid, with many new structures and target combinations being created. The boom in bsAbs has led to the successive issuance of industry guidance for their development in the US and China. However, there is a high degree of similarity in target selection, which could affect the development of diversity in bsAbs. This review presents a classification of various bsAbs for cancer therapy based on structure and target selection and examines the advantages of bsAbs over monoclonal antibodies (mAbs). Through database research, we have identified the preferences of available bsAbs combinations, suggesting rational target selection options and warning of potential wastage of medical resources. We have also compared the US and Chinese guidelines for bsAbs in order to provide a reference for their development.
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Affiliation(s)
- Yanze Sun
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Xinmiao Yu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Xiao Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Kai Yuan
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Gefei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Lingrong Hu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Guoyu Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Wenli Pei
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Liping Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Chengliang Sun
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Peng Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
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Valentin JP, Sibony A, Rosseels ML, Delaunois A. "Appraisal of state-of-the-art" The 2021 Distinguished Service Award of the Safety Pharmacology Society: Reflecting on the past to tackle challenges ahead. J Pharmacol Toxicol Methods 2023; 123:107269. [PMID: 37149063 DOI: 10.1016/j.vascn.2023.107269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/03/2023] [Indexed: 05/08/2023]
Abstract
This appraisal of state-of-the-art manuscript highlights and expands upon the thoughts conveyed in the lecture of Dr. Jean-Pierre Valentin, recipient of the 2021 Distinguished Service Award of the Safety Pharmacology Society, given on the 2nd December 2021. The article reflects on the strengths, weaknesses, opportunities, and threats that surrounded the evolution of safety and secondary pharmacology over the last 3 decades with a particular emphasis on pharmaceutical drug development delivery, scientific and technological innovation, complexities of regulatory framework and people leadership and development. The article further built on learnings from past experiences to tackle constantly emerging issues and evolving landscape whilst being cognizant of the challenges facing these disciplines in the broader drug development and societal context.
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Affiliation(s)
- Jean-Pierre Valentin
- UCB-Biopharma SRL, Early Solutions, Development Science, Non-Clinical Safety Evaluation, Braine L'Alleud, Belgium.
| | - Alicia Sibony
- UCB-Biopharma SRL, Early Solutions, Development Science, Non-Clinical Safety Evaluation, Braine L'Alleud, Belgium
| | - Marie-Luce Rosseels
- UCB-Biopharma SRL, Early Solutions, Development Science, Non-Clinical Safety Evaluation, Braine L'Alleud, Belgium
| | - Annie Delaunois
- UCB-Biopharma SRL, Early Solutions, Development Science, Non-Clinical Safety Evaluation, Braine L'Alleud, Belgium
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Zhang X, Li Z. Investigating industrial PAH air pollution in relation to population exposure in major countries: A scoring approach. J Environ Manage 2023; 338:117801. [PMID: 36996564 DOI: 10.1016/j.jenvman.2023.117801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 03/17/2023] [Accepted: 03/22/2023] [Indexed: 06/19/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are common air pollutants worldwide, associated with industrial processes. In the general population, both modeling and field studies revealed a positive correlation between air PAH concentrations and urinary PAH metabolite levels. Many countries lack population urinary data that correspond to local PAH air concentrations. Thus, we proposed a scoring-based approximate approach to investigating that correlation in selected countries, hypothesizing that PAH air concentrations in selected regions could represent the national air quality influenced by industrial emission and further correlate to PAH internal exposure in the general population. This research compiled 85 peer-reviewed journal articles and 9 official monitoring datasets/reports covering 34 countries, 16 of which with both atmospheric PAH data and human biomonitoring data. For the air pollution score (AirS), Egypt had the highest AirS at 0.94 and Pakistan was at the bottom of the score ranking at -1.95, as well as the median in the UK (AirS: 0.50). For the population exposure score (ExpS), China gained the top ExpS at 0.44 and Spain was with the lowest ExpS of -1.52, with the median value in Italy (ExpS: 0.43). Through the correlation analysis, atmospheric PAHs and their corresponding urinary metabolites provided a positive relationship to a diverse extent, indicating that the related urinary metabolites could reflect the population's exposure to specific atmospheric PAHs. The findings also revealed that in the 16 selected countries, AirS indexes were positively correlated with ExpS indexes, implying that higher PAH levels in the air may lead to elevated metabolite urinary levels in general populations. Furthermore, lowering PAH air concentrations could reduce population internal PAH exposure, implying that strict PAH air regulation or emission would reduce health risks for general populations. Notably, this study was an ideal theoretical research based on proposed assumptions to some extent. Further research should focus on understanding exposure pathways, protecting vulnerable populations, and improving the PAH database to optimize PAH pollution control.
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Affiliation(s)
- Xiaoyu Zhang
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Zijian Li
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 518107, China.
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Miners JO, Polasek TM, Hulin JA, Rowland A, Meech R. Drug-drug interactions that alter the exposure of glucuronidated drugs: Scope, UDP-glucuronosyltransferase (UGT) enzyme selectivity, mechanisms (inhibition and induction), and clinical significance. Pharmacol Ther 2023:108459. [PMID: 37263383 DOI: 10.1016/j.pharmthera.2023.108459] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 06/03/2023]
Abstract
Drug-drug interactions (DDIs) arising from the perturbation of drug metabolising enzyme activities represent both a clinical problem and a potential economic loss for the pharmaceutical industry. DDIs involving glucuronidated drugs have historically attracted little attention and there is a perception that interactions are of minor clinical relevance. This review critically examines the scope and aetiology of DDIs that result in altered exposure of glucuronidated drugs. Interaction mechanisms, namely inhibition and induction of UDP-glucuronosyltransferase (UGT) enzymes and the potential interplay with drug transporters, are reviewed in detail, as is the clinical significance of known DDIs. Altered victim drug exposure arising from modulation of UGT enzyme activities is relatively common and, notably, the incidence and importance of UGT induction as a DDI mechanism is greater than generally believed. Numerous DDIs are clinically relevant, resulting in either loss of efficacy or an increased risk of adverse effects, necessitating dose individualisation. Several generalisations relating to the likelihood of DDIs can be drawn from the known substrate and inhibitor selectivities of UGT enzymes, highlighting the importance of comprehensive reaction phenotyping studies at an early stage of drug development. Further, rigorous assessment of the DDI liability of new chemical entities that undergo glucuronidation to a significant extent has been recommended recently by regulatory guidance. Although evidence-based approaches exist for the in vitro characterisation of UGT enzyme inhibition and induction, the availability of drugs considered appropriate for use as 'probe' substrates in clinical DDI studies is limited and this should be research priority.
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Affiliation(s)
- John O Miners
- Discipline of Clinical Pharmacology and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine and Public Health, Flinders University, Adelaide, Australia.
| | - Thomas M Polasek
- Certara, Princeton, NJ, USA; Centre for Medicines Use and Safety, Monash University, Melbourne, Australia
| | - Julie-Ann Hulin
- Discipline of Clinical Pharmacology and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Andrew Rowland
- Discipline of Clinical Pharmacology and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Robyn Meech
- Discipline of Clinical Pharmacology and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine and Public Health, Flinders University, Adelaide, Australia
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Halsey N, Evans S, Santosham M, Hacker A, Edwards KM, Chandler RE, Dudley MZ, Dekker CL, Al-Abri S, Arora N, Buttery J, Dodoo A, Eskola J, Heininger U, Jee Y, Khuri N, Obaro S, Orenstein W, Pitisuttithum P, Safadi M, Whitney CG, Black S. Considerations for unblinding individual study participants during vaccine trials. Vaccine 2023; 41:3399-3402. [PMID: 37121805 DOI: 10.1016/j.vaccine.2023.04.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 03/26/2023] [Accepted: 04/11/2023] [Indexed: 05/02/2023]
Abstract
Premature unblinding of individual participants is rarely reported in publications, but such unblinding can disrupt vaccine trials by causing worry and drop-out of other participants or "pseudo unblinding," in which participants or investigators over-interpret certain symptoms as being related to receiving an investigational product. This review summarizes appropriate reasons for unblinding in vaccine trials. Regulatory guidance could be improved by distinguishing guidance for vaccine trials from drug trials, with the recognition that unblinding individual participants in vaccine studies is rarely needed for management of adverse events following immunization.
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Affiliation(s)
- Neal Halsey
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States.
| | - Stephen Evans
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Mathuram Santosham
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Adam Hacker
- Coalition for Epidemic Preparedness Innovations, Norway
| | | | | | - Matthew Z Dudley
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | | | - Seif Al-Abri
- Directorate General for Disease Surveillance and Control, Muscat, Oman
| | - Narendra Arora
- Executive Director of The INCLEN Trust International, India
| | | | | | - Juhani Eskola
- National Institute for Health and Wellfare, Helsinki, Finland
| | | | | | | | - Stephen Obaro
- University of Nebraska Medical Center, United States
| | | | | | | | | | - Steve Black
- Global Vaccine Data Network, Auckland, New Zealand
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Valentin JP, Leishman D. 2000-2023 over two decades of ICH S7A: has the time come for a revamp? Regul Toxicol Pharmacol 2023; 139:105368. [PMID: 36841350 DOI: 10.1016/j.yrtph.2023.105368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 02/06/2023] [Accepted: 02/19/2023] [Indexed: 02/27/2023]
Abstract
The ICH S7A guideline on safety pharmacology studies released over 20 years ago largely achieved its objective "to help protect clinical trial participants and patients receiving marketed products from potential adverse effects of pharmaceuticals". Although, Phase I clinical trials are generally very safe, the incidence and severity of adverse events, the safety related attrition and product withdrawal remain elevated during late-stage clinical development and post approval, a proportion of which can be attributed at least in part to safety pharmacology related issues. Considering the latest scientific and technological advancements in drug safety science, the paradigm shift of the drug discovery and development process and the continuously evolving regulatory landscape, we recommend revisiting, adapting and evolving the ICH S7A guideline. This might offer opportunities i) to select and progress optimized drugs with increased confidence in success, ii) to refine and adapt the clinical monitoring at all stages of clinical development resulting in an optimized benefit/risk assessment, iii) to increase likelihood of regulatory acceptance in a way compatible with an expedited and streamlined drug discovery and development process to benefit patients and iv) to avoid the unnecessary use of animals in 'tick-the-box' studies and encourage alternative approaches. As presented in the article, several options could be envisioned to revisit and adapt the ICH S7A taking into consideration several key features.
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Affiliation(s)
- Jean-Pierre Valentin
- UCB-Biopharma SRL, Early Solutions, Development Science, Non-Clinical Safety Evaluation, Braine L'Alleud, Belgium.
| | - Derek Leishman
- Drug Disposition, Toxicology and PKPD, Eli Lilly and Company, Indianapolis, IN, 46285, USA.
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De Sutter E, Borry P, Huys I, Barbier L. Informing a European guidance framework on electronic informed consent in clinical research: a qualitative study. BMC Health Serv Res 2023; 23:181. [PMID: 36810088 PMCID: PMC9942635 DOI: 10.1186/s12913-023-09173-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/13/2023] [Indexed: 02/23/2023] Open
Abstract
BACKGROUND Electronic informed consent (eIC) may offer various advantages compared to paper-based informed consent. However, the regulatory and legal landscape related to eIC provides a diffuse image. By drawing from the perspectives of key stakeholders in the field, this study aims to inform the creation of a European guidance framework on eIC in clinical research. METHODS Focus group discussions and semi-structured interviews were conducted with 20 participants from six stakeholder groups. The stakeholder groups included representatives of ethics committees, data infrastructure organizations, patient organizations, and the pharmaceutical industry as well as investigators and regulators. All were involved in or knowledgeable about clinical research and were active in one of the European Union Member States or at a pan-European or global level. The framework method was used for data analysis. RESULTS Stakeholders underwrote the need for a multi-stakeholder guidance framework addressing practical elements related to eIC. According to the stakeholders, a European guidance framework should describe consistent requirements and procedures for implementing eIC on a pan-European level. Generally, stakeholders agreed with the definitions of eIC issued by the European Medicines Agency and the US Food and Drug Administration. Nevertheless, it was raised that, in a European guidance framework, it should be emphasized that eIC aims to support rather than replace the personal interaction between research participants and the research team. In addition, it was believed that a European guidance framework should include details on the legality of eIC across European Union Member States and the responsibilities of an ethics committee in the eIC assessment process. Although stakeholders supported the idea to include detailed information on the type of eIC-related materials to be submitted to an ethics committee, opinions varied on this regard. CONCLUSION The creation of a European guidance framework is a much needed factor to advance eIC implementation in clinical research. By collecting the views of multiple stakeholder groups, this study advances recommendations that may facilitate the development of such a framework. Particular consideration should go to harmonizing requirements and providing practical details related to eIC implementation on a European Union-wide level.
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Affiliation(s)
- Evelien De Sutter
- Clinical Pharmacology and Pharmacotherapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
| | - Pascal Borry
- grid.5596.f0000 0001 0668 7884Centre for Biomedical Ethics and Law, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium
| | - Isabelle Huys
- grid.5596.f0000 0001 0668 7884Clinical Pharmacology and Pharmacotherapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Liese Barbier
- grid.5596.f0000 0001 0668 7884Clinical Pharmacology and Pharmacotherapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
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Kantak MN, Bharate SS. Analysis of clinical trials on biomaterial and therapeutic applications of chitosan: A review. Carbohydr Polym 2022; 278:118999. [PMID: 34973801 DOI: 10.1016/j.carbpol.2021.118999] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/04/2021] [Accepted: 12/06/2021] [Indexed: 02/07/2023]
Abstract
Chitosan is a modified natural carbohydrate polymer derived from chitin that occurs in many natural sources. It has a diverse range of applications in medical and pharmaceutical sciences. Its primary and permitted use is biomaterial in medical devices. Chitosan and its derivatives also find utility in pharmaceuticals as an excipient, drug carrier, or therapeutic agent. The USFDA has approved chitosan usage as a biomaterial but not for pharmaceutical use, primarily because of the concerns over its source, purity, and immunogenicity. A large number of clinical studies are underway on chitosan-based materials/ products because of their diverse applications. Herein, we analyze clinical studies to understand their clinical usage portfolio. Our analysis shows that >100 clinical studies are underway to investigate the safety/efficacy of chitosan or its biomaterials/ nanoparticles, comprising ~95% interventional and ~ 5% observational studies. The regulatory considerations that limit the use of chitosan in pharmaceuticals are also deliberated. TEASER: Clinical Trials of Chitosan.
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Affiliation(s)
- Maithili N Kantak
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS, V.L. Mehta Road, Vile Parle (W), Mumbai 400056, India
| | - Sonali S Bharate
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS, V.L. Mehta Road, Vile Parle (W), Mumbai 400056, India.
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Myler H, Pedras-Vasconcelos J, Phillips K, Hottenstein CS, Chamberlain P, Devanaryan V, Gleason C, Goodman J, Manning MS, Purushothama S, Richards S, Shen H, Zoghbi J, Amaravadi L, Barger T, Bowen S, Bowsher RR, Clements-Egan A, Geng D, Goletz TJ, Gunn GR, Hallett W, Hodsdon ME, Janelsins BM, Jawa V, Kamondi S, Kirshner S, Kramer D, Liang M, Lindley K, Liu S, Liu Z, McNally J, Mikulskis A, Nelson R, Ahbari MR, Qu Q, Ruppel J, Snoeck V, Song A, Yan H, Ware M. Anti-drug Antibody Validation Testing and Reporting Harmonization. AAPS J 2021; 24:4. [PMID: 34853961 PMCID: PMC8816448 DOI: 10.1208/s12248-021-00649-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 09/20/2021] [Indexed: 11/30/2022] Open
Abstract
Evolving immunogenicity assay performance expectations and a lack of harmonized anti-drug antibody validation testing and reporting tools have resulted in significant time spent by health authorities and sponsors on resolving filing queries. Following debate at the American Association of Pharmaceutical Sciences National Biotechnology Conference, a group was formed to address these gaps. Over the last 3 years, 44 members from 29 organizations (including 5 members from Europe and 10 members from FDA) discussed gaps in understanding immunogenicity assay requirements and have developed harmonization tools for use by industry scientists to facilitate filings to health authorities. Herein, this team provides testing and reporting strategies and tools for the following assessments: (1) pre-study validation cut point; (2) in-study cut points, including procedures for applying cut points to mixed populations; (3) system suitability control criteria for in-study plate acceptance; (4) assay sensitivity, including the selection of an appropriate low positive control; (5) specificity, including drug and target tolerance; (6) sample stability that reflects sample storage and handling conditions; (7) assay selectivity to matrix components, including hemolytic, lipemic, and disease state matrices; (8) domain specificity for multi-domain therapeutics; (9) and minimum required dilution and extraction-based sample processing for titer reporting.
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Affiliation(s)
- Heather Myler
- Immunochemistry Department, PPD Laboratories, 2244 Dabney Road, Richmond, Virginia, 23230-3323, USA.
| | - João Pedras-Vasconcelos
- Product Quality and Immunogenicity, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, 20903, USA
| | - Kelli Phillips
- Immunochemistry Department, PPD Laboratories, 2244 Dabney Road, Richmond, Virginia, 23230-3323, USA
| | - Charles Scott Hottenstein
- Immunogenicity, GlaxoSmithKline Pharmaceuticals, 1250 South Collegeville Road, Collegeville, Pennsylvania, 19426, USA
| | - Paul Chamberlain
- NDA Advisory Services, Ltd., Grove House, Guildford Road, Leatherhead, KT22 9DF, Surrey, UK
| | | | - Carol Gleason
- Global Biometric and Data Sciences, Bristol-Myers Squibb, Princeton, New Jersey, 08540, USA
| | - Joanne Goodman
- Integrated Bioanalysis, Clinical Pharmacology and Safety Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | | | - Shobha Purushothama
- Diagnostics Accelerator, Alzheimer's Drug Discovery Foundation, 57W 57th Street, New York, New York, USA
| | - Susan Richards
- Translational Medicine and Early Development, Sanofi, Framingham, Massachusetts, 01701, USA
| | - Honglue Shen
- Specialty Bioanalytics, Teva Pharmaceuticals, West Chester, Pennsylvania, 19380, USA
| | - Jad Zoghbi
- Translational Medicine and Early Development, Sanofi, Framingham, Massachusetts, 01701, USA
| | | | - Troy Barger
- Bioanalytical Sciences, Amgen Research, Thousand Oaks, California, 91320, USA
| | - Steven Bowen
- Product Quality and Immunogenicity, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, 20903, USA
| | - Ronald R Bowsher
- B2S Life Sciences, 97 East Monroe Street, Franklin, Indiana, 46131, USA
| | | | - Dong Geng
- Legend Biotech, 10 Knightsbridge Road, Piscataway, New Jersey, 08554, USA
| | - Theresa J Goletz
- Drug Metabolism & Pharmacokinetics, EMD Serono, Billerica, Massachusetts, 01821, USA
| | - George R Gunn
- Immunogenicity, GlaxoSmithKline Pharmaceuticals, 1250 South Collegeville Road, Collegeville, Pennsylvania, 19426, USA
| | - William Hallett
- Product Quality and Immunogenicity, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, 20903, USA
| | - Michael E Hodsdon
- Laboratory for Experimental Medicine, Eli Lilly and Company, Indianapolis, Indiana, 46285, USA
| | - Brian M Janelsins
- Product Quality and Immunogenicity, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, 20903, USA
| | - Vibha Jawa
- Predictive and Clinical Immunogenicity Pharmacometrics, Pharmacodynamics and Drug Metabolism, Merck and Co., 2000 Galloping Hill Road, Kenilworth, New Jersey, 07033, USA
| | - Szilard Kamondi
- Kamondi Bioanalytical Consultancy, Rheinfelden, Switzerland / Roche Pharma Research & Early Development, Pharmaceutical Sciences, Bioanalytical R&D, Roche Innovation Center, Basel, Switzerland
| | - Susan Kirshner
- Product Quality and Immunogenicity, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, 20903, USA
| | - Daniel Kramer
- Translational Medicine and Early Development, Sanofi, Frankfurt am Main, Germany
| | - Meina Liang
- Integrated Bioanalysis, Clinical Pharmacology and Safety Sciences, BioPharmaceuticals R&D, AstraZeneca, South San Francisco, California, USA
| | | | - Susana Liu
- Pfizer Inc., 17300 Trans Canada Hwy, Kirkland, Quebec, Canada
| | - ZhenZhen Liu
- Product Quality and Immunogenicity, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, 20903, USA
| | - Jim McNally
- BioAgilytix Labs, Durham, North Carolina, 27713, USA
| | - Alvydas Mikulskis
- Clinical Biomarkers, Vertex Pharmaceuticals, Inc., Boston, Massachusetts, 02210, USA
| | - Robert Nelson
- Immunochemistry Department, Covance Laboratories Ltd., Harrogate, HG3 1PY, UK
| | - Mohsen Rajabi Ahbari
- Office of Study Integrity and Surveillance, Office of Translational Sciences, Center for Drug Evaluation and Research (CDER), Food and Drug Administration, Silver Spring, Maryland, 20993, USA
| | - Qiang Qu
- Global Product Development, Pfizer Inc., Andover, Massachusetts, 01810, USA
| | - Jane Ruppel
- BioAnalytical Sciences, Genentech, South San Francisco, California, USA
| | - Veerle Snoeck
- Translational Biomarkers and Bioanalysis, UCB Biopharma SRL, B-1420, Braine-l'Alleud, Belgium
| | - An Song
- Development Sciences, Immune-Onc Therapeutics, Palo Alto, California, 94303, USA
| | - Haoheng Yan
- Product Quality and Immunogenicity, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, 20903, USA
| | - Mark Ware
- Janssen BioTherapeutics, Janssen R&D LLC, Spring House, Pennsylvania, 19477, USA
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Gaston TE, Mendrick DL, Paine MF, Roe AL, Yeung CK. "Natural" is not synonymous with "Safe": Toxicity of natural products alone and in combination with pharmaceutical agents. Regul Toxicol Pharmacol 2020; 113:104642. [PMID: 32197968 DOI: 10.1016/j.yrtph.2020.104642] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/05/2020] [Accepted: 03/12/2020] [Indexed: 02/07/2023]
Abstract
During the 25 years since the US Congress passed the Dietary Supplement Health and Education Act (DSHEA), the law that transformed the US Food and Drug Administration's (FDA's) authority to regulate dietary supplements, the dietary supplement market has grown exponentially. Retail sales of herbal products, a subcategory of dietary supplements, have increased 83% from 2008 to 2018 ($4.8 to $8.8 billion USD). Although consumers often equate "natural" with "safe", it is well recognized by scientists that constituents in these natural products (NPs) can result in toxicity. Additionally, when NPs are co-consumed with pharmaceutical agents, the precipitant NP can alter drug disposition and drug delivery, thereby enhancing or reducing the therapeutic effect of the object drug(s). With the widespread use of NPs, these effects can be underappreciated. We present a summary of a symposium presented at the Annual Meeting of the Society of Toxicology 2019 (12 March 2019) that discussed potential toxicities of NPs alone and in combination with drugs.
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Affiliation(s)
- Tyler E Gaston
- Department of Neurology, University of Alabama at Birmingham, United States
| | - Donna L Mendrick
- National Center for Toxicological Research, United States Food and Drug Administration, United States
| | - Mary F Paine
- Department of Pharmaceutical Sciences, Washington State University, United States
| | - Amy L Roe
- The Procter & Gamble Company, United States
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11
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Nowak C, K Cheung J, M Dellatore S, Katiyar A, Bhat R, Sun J, Ponniah G, Neill A, Mason B, Beck A, Liu H. Forced degradation of recombinant monoclonal antibodies: A practical guide. MAbs 2017; 9:1217-1230. [PMID: 28853987 DOI: 10.1080/19420862.2017.1368602] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Forced degradation studies have become integral to the development of recombinant monoclonal antibody therapeutics by serving a variety of objectives from early stage manufacturability evaluation to supporting comparability assessments both pre- and post- marketing approval. This review summarizes the regulatory guidance scattered throughout different documents to highlight the expectations from various agencies such as the Food and Drug Administration and European Medicines Agency. The various purposes for forced degradation studies, commonly used conditions and the major degradation pathways under each condition are also discussed.
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Affiliation(s)
- Christine Nowak
- a Product Characterization, Alexion Pharmaceuticals , New Haven , CT , USA
| | - Jason K Cheung
- b Sterile Formulation Sciences, MRL , Merck & Co., Inc. , Kenilworth , NJ, USA , USA
| | - Shara M Dellatore
- c Biologics and Vaccines Bioanalytics, MRL , Merck & Co., Inc. , Kenilworth , NJ , USA
| | - Amit Katiyar
- d Analytical Development, Bristol-Myers Squibb , Pennington , NJ , USA
| | - Ram Bhat
- e Millennium Research laboratories , Woburn , MA , USA
| | - Joanne Sun
- f Product Development, Innovent Biologics , Suzhou Industrial Park, China
| | | | - Alyssa Neill
- a Product Characterization, Alexion Pharmaceuticals , New Haven , CT , USA
| | - Bruce Mason
- a Product Characterization, Alexion Pharmaceuticals , New Haven , CT , USA
| | - Alain Beck
- g Analytical Chemistry, NBEs, Center d'Immunology Pierre Fabre , Cedex , France
| | - Hongcheng Liu
- a Product Characterization, Alexion Pharmaceuticals , New Haven , CT , USA
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Bakker F. Design and analysis of field studies with bees: A critical review of the draft EFSA guidance. Integr Environ Assess Manag 2016; 12:422-8. [PMID: 26436642 DOI: 10.1002/ieam.1716] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/20/2015] [Accepted: 09/28/2015] [Indexed: 05/02/2023]
Abstract
The specific protection goal, primary assessment endpoints, acceptable effect thresholds, and experimental design proposed in the European Food Safety Authority (EFSA) update of the bee guidance document are subjected to critical review. It is concluded that the negligible effect criteria were established without sufficient regulatory definition and without convincing scientific argumentation. For the assessment endpoints, effects on hive strength lack temporal definition and the reduction to numbers of bees is inappropriate to evaluate effects. Restricting mortality assessments to homing failure is not theoretically justified and specific criteria were incorrectly derived. The combination of acute effect estimates with models for chronic stressors is biased risk assessment and a temporal basis for the acceptability of effects is missing. Effects on overwintering success cannot be experimentally assessed using the proposed criteria. The experimental methodology proposed is inappropriate and the logistical consequences, in particular those related to replication and land use are such that field studies are no longer a feasible option for the risk assessment. It may be necessary to explore new lines of thought for the set-up of field studies and to clearly separate experimentation from monitoring. Integr Environ Assess Manag 2016;12:422-428. © 2015 SETAC.
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Abstract
UNLABELLED In 2014, the members of the BioPhorum Operations Group (BPOG) produced a 100-page continued process verification case study, entitled "Continued Process Verification: An Industry Position Paper with Example Protocol". This case study captures the thought processes involved in creating a continued process verification plan for a new product in response to the U.S. Food and Drug Administration's guidance on the subject introduced in 2011. In so doing, it provided the specific example of a plan developed for a new molecular antibody product based on the "A MAb Case Study" that preceded it in 2009.This document provides a roadmap that draws on the content of the continued process verification case study to provide a step-by-step guide in a more accessible form, with reference to a process map of the product life cycle. It could be used as a basis for continued process verification implementation in a number of different scenarios: For a single product and process;For a single site;To assist in the sharing of data monitoring responsibilities among sites;To assist in establishing data monitoring agreements between a customer company and a contract manufacturing organization. LAY ABSTRACT The U.S. Food and Drug Administration issued guidance on the management of manufacturing processes designed to improve quality and control of drug products. This involved increased focus on regular monitoring of manufacturing processes, reporting of the results, and the taking of opportunities to improve. The guidance and practice associated with it is known as continued process verification This paper summarizes good practice in responding to continued process verification guidance, gathered from subject matter experts in the biopharmaceutical industry.
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Affiliation(s)
- Marcus Boyer
- Associate Director and Senior Scientist, Process Validation, Bristol-Myers Squibb, East Syracuse, NY, USA
| | - Joerg Gampfer
- Head of Commercial Manufacturability and Platforms, Baxalta, Vienna, Austria
| | - Abdel Zamamiri
- Abdelqader Zamamiri, Ph.D., Associate Director, Process Data Management, Regeneron, Rensselaer, NY, USA
| | - Robin Payne
- Abdelqader Zamamiri, Ph.D., Associate Director, Process Data Management, Regeneron, Rensselaer, NY, USA
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14
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Kadian N, Raju KSR, Rashid M, Malik MY, Taneja I, Wahajuddin M. Comparative assessment of bioanalytical method validation guidelines for pharmaceutical industry. J Pharm Biomed Anal 2016; 126:83-97. [PMID: 27179186 DOI: 10.1016/j.jpba.2016.03.052] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 03/24/2016] [Indexed: 10/22/2022]
Abstract
The concepts, importance, and application of bioanalytical method validation have been discussed for a long time and validation of bioanalytical methods is widely accepted as pivotal before they are taken into routine use. United States Food and Drug Administration (USFDA) guidelines issued in 2001 have been referred for every guideline released ever since; may it be European Medical Agency (EMA) Europe, National Health Surveillance Agency (ANVISA) Brazil, Ministry of Health and Labour Welfare (MHLW) Japan or any other guideline in reference to bioanalytical method validation. After 12 years, USFDA released its new draft guideline for comments in 2013, which covers the latest parameters or topics encountered in bioanalytical method validation and approached towards the harmonization of bioanalytical method validation across the globe. Even though the regulatory agencies have general agreement, significant variations exist in acceptance criteria and methodology. The present review highlights the variations, similarities and comparison between bioanalytical method validation guidelines issued by major regulatory authorities worldwide. Additionally, other evaluation parameters such as matrix effect, incurred sample reanalysis including other stability aspects have been discussed to provide an ease of access for designing a bioanalytical method and its validation complying with the majority of drug authority guidelines.
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Affiliation(s)
- Naveen Kadian
- Department of Pharmacokinetics and Metabolism, CSIR-Central Drug Research Institute, Lucknow, India
| | - Kanumuri Siva Rama Raju
- Department of Pharmacokinetics and Metabolism, CSIR-Central Drug Research Institute, Lucknow, India; Academy of Scientific and Industrial Research, New Delhi, India
| | - Mamunur Rashid
- Department of Pharmacokinetics and Metabolism, CSIR-Central Drug Research Institute, Lucknow, India
| | - Mohd Yaseen Malik
- Department of Pharmacokinetics and Metabolism, CSIR-Central Drug Research Institute, Lucknow, India
| | - Isha Taneja
- Department of Pharmacokinetics and Metabolism, CSIR-Central Drug Research Institute, Lucknow, India; Academy of Scientific and Industrial Research, New Delhi, India
| | - Muhammad Wahajuddin
- Department of Pharmacokinetics and Metabolism, CSIR-Central Drug Research Institute, Lucknow, India; Academy of Scientific and Industrial Research, New Delhi, India.
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Beulke S, van Beinum W, Suddaby L. Interpretation of aged sorption studies for pesticides and their use in European Union regulatory leaching assessments. Integr Environ Assess Manag 2015; 11:276-286. [PMID: 25565626 DOI: 10.1002/ieam.1607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/11/2014] [Accepted: 10/28/2014] [Indexed: 06/04/2023]
Abstract
First-tier regulatory exposure assessments for pesticides assume that pesticide sorption is instantaneous and fully reversible. In European Union (EU) regulatory guidance, an increase in sorption over time ("aged sorption") can be considered at the higher tier to refine predicted environmental concentrations in groundwater. Research commissioned by the UK Chemicals Regulation Directorate (CRD), funded by the Department for Environment Food & Rural Affairs (Defra), formed the basis of a draft regulatory guidance document proposing 1) a protocol on how to measure aged sorption of parent compounds in laboratory studies, 2) procedures to fit kinetic models to the experimental data, 3) criteria to test the reliability of the parameters, and 4) procedures for use of the parameters in the groundwater exposure assessment. The draft guidance was revised after feedback from stakeholders and testing of the guidance was performed against real data sets by an independent consultancy. The Chemicals Regulation Directorate submitted the revised document to the European Food Safety Authority (EFSA) for scrutiny. This article gives an overview of the draft guidance and explains the reasoning behind the recommendations made.
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Affiliation(s)
- Sabine Beulke
- The Food and Environment Research Agency, Sand Hutton, York, United Kingdom
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Cavagnaro J, Silva Lima B. Regulatory acceptance of animal models of disease to support clinical trials of medicines and advanced therapy medicinal products. Eur J Pharmacol 2015; 759:51-62. [PMID: 25814257 DOI: 10.1016/j.ejphar.2015.03.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 02/26/2015] [Accepted: 03/12/2015] [Indexed: 11/30/2022]
Abstract
The utility of animal models of disease for assessing the safety of novel therapeutic modalities has become an increasingly important topic of discussion as research and development efforts focus on improving the predictive value of animal studies to support accelerated clinical development. Medicines are approved for marketing based upon a determination that their benefits outweigh foreseeable risks in specific indications, specific populations, and at specific dosages and regimens. No medicine is 100% safe. A medicine is less safe if the actual risks are greater than the predicted risks. The purpose of preclinical safety assessment is to understand the potential risks to aid clinical decision-making. Ideally preclinical studies should identify potential adverse effects and design clinical studies that will minimize their occurrence. Most regulatory documents delineate the utilization of conventional "normal" animal species to evaluate the safety risk of new medicines (i.e., new chemical entities and new biological entities). Animal models of human disease are commonly utilized to gain insight into the pathogenesis of disease and to evaluate efficacy but less frequently utilized in preclinical safety assessment. An understanding of the limitations of the animal disease models together with a better understanding of the disease and how toxicity may be impacted by the disease condition should allow for a better prediction of risk in the intended patient population. Importantly, regulatory authorities are becoming more willing to accept and even recommend data from experimental animal disease models that combine efficacy and safety to support clinical development.
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Abstract
The February 2013 Food and Drug Administration (FDA) draft guidance for developing drugs for early-stage Alzheimer's disease (AD) creates certain challenges as they guide toward the use of one cognitive outcome to gain accelerated marketing approval for preclinical AD drugs, and a composite clinical scale - the Clinical Dementia Rating Scale in particular - for the primary outcome for prodromal AD clinical trials. In light of the developing knowledge regarding early stage diagnoses and clinical trials outcomes, we recommend that FDA describe its requirements for validating preclinical AD diagnoses for drug development purposes, maintain the principle for requiring coprimary outcomes, and encourage the advancement of outcomes for early stage AD trials. The principles for drug development for early stage AD should not differ from those for clinical AD, especially as the diagnoses of prodromal and early AD impinge on each other. The FDA should not recommend that a composite scale be used as a sole primary efficacy outcome to support a marketing claim unless it requires that the cognitive and functional components of such a scale are demonstrated to be individually meaningful. The current draft guidelines may inadvertently constrain efforts to better assess the clinical effects of new drugs and inhibit innovation in an area where evidence-based clinical research practices are still evolving.
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Affiliation(s)
- Lon S Schneider
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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Krajcsi P. Drug-transporter interaction testing in drug discovery and development. World J Pharmacol 2013; 2:35-46. [DOI: 10.5497/wjp.v2.i1.35] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/25/2012] [Accepted: 01/30/2013] [Indexed: 02/06/2023] Open
Abstract
The human body consists of several physiological barriers that express a number of membrane transporters. For an orally absorbed drug the intestinal, hepatic, renal and blood-brain barriers are of the greatest importance. The ATP-binding cassette (ABC) transporters that mediate cellular efflux and the solute carrier transporters that mostly mediate cellular uptake are the two superfamilies responsible for membrane transport of vast majority of drugs and drug metabolites. The total number of human transporters in the two superfamilies exceeds 400, and about 40-50 transporters have been characterized for drug transport. The latest Food and Drug Administration guidance focuses on P-glycoprotein, breast cancer resistance protein, organic anion transporting polypeptide 1B1 (OATP1B1), OATP1B3, organic cation transporter 2 (OCT2), and organic anion transporters 1 (OAT1) and OAT3. The European Medicines Agency’s shortlist additionally contains the bile salt export pump, OCT1, and the multidrug and toxin extrusion transporters, multidrug and toxin extrusion protein 1 (MATE1) and MATE2/MATE2K. A variety of transporter assays are available to test drug-transporter interactions, transporter-mediated drug-drug interactions, and transporter-mediated toxicity. The drug binding site of ABC transporters is accessible from the cytoplasm or the inner leaflet of the plasma membrane. Therefore, vesicular transport assays utilizing inside-out vesicles are commonly used assays, where the directionality of transport results in drugs being transported into the vesicle. Monolayer assays utilizing polarized cells expressing efflux transporters are the test systems suggested by regulatory agencies. However, in some monolayers, uptake transporters must be coexpressed with efflux transporters to assure detectable transport of low passive permeability drugs. For uptake transporters mediating cellular drug uptake, utilization of stable transfectants have been suggested. In vivo animal models complete the testing battery. Some issues, such as in vivo relevance, gender difference, age and ontogeny issues can only be addressed using in vivo models. Transporter specificity is provided by using knock-out or mutant models. Alternatively, chemical knock-outs can be employed. Compensatory changes are less likely when using chemical knock-outs. On the other hand, specific inhibitors for some uptake transporters are not available, limiting the options to genetic knock-outs.
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