1
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Alamin M, Oladipo P, Hartrick J, Islam N, Bahmani A, Turner CL, Shuster W, Ram JL. Improved passive sampling methods for wastewater to enable more sensitive detection of SARS-CoV-2 and its variants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175044. [PMID: 39074755 DOI: 10.1016/j.scitotenv.2024.175044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 07/03/2024] [Accepted: 07/24/2024] [Indexed: 07/31/2024]
Abstract
Wastewater-based epidemiology (WBE) can be used as a part of a long-term strategy for detecting and responding rapidly to new outbreaks of infectious disease in the community. However, wastewater collected by grab samples may miss marker presence, and composite auto-sampling throughout a day is technically challenging and costly. Tampon swabs can be used as passive collectors of wastewater markers over hours, but recovery of the captured markers is a challenge. Our goal was to improve tampon elution methods for virus detection and variant analysis to increase the likelihood of detection near the Limit of Detection (LOD) and to potentially detect new or rare variants in a new outbreak. Counts of SARS-CoV-2 N1 and N2 markers in grab samples were compared to markers eluted from tampons that had been immersed in 3 sewersheds for 4-6 h during June to December 2023. We compared tampon elution methods that used different elution volumes, pressure, and amounts of Tween 20, evaluated after automated magnetic bead purification and RT-ddPCR of SARS-CoV-2 markers. Overall, method "SwabM2" in which tampons were eluted by high pressure squeeze in a 50 mL syringe after adding 2 mL of 0.5 X TE + 0.075 % Tween-20 yielded a median four-fold higher concentration of final purified SARS-CoV-2 markers than paired grab samples and significantly more than other tested tampon elution methods (p < 0.0001). Method SwabM2 was more likely to yield enough extracted nucleic acids for sequencing and also gave higher quality variant sequences than two other tampon elution methods. Variant analysis captured the Fall 2023 transition of variants from XBB to JN and "H" lineages. In summary, we demonstrated a tampon-based wastewater collecting and elution method that yielded higher counts, more detections near the LOD, and higher quality variant sequences compared to both grab samples and other tampon-based passive-collecting wastewater methods.
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Affiliation(s)
- Md Alamin
- Department of Physiology, Wayne State University, Detroit, MI 48201, United States of America.
| | - Pelumi Oladipo
- Department of Biochemistry, Microbiology, & Immunology, Wayne State University, Detroit, MI 48201, United States of America
| | - James Hartrick
- LimnoTech, 501 Avis Dr., Ann Arbor, MI 48108, United States of America
| | - Natasha Islam
- Department of Physiology, Wayne State University, Detroit, MI 48201, United States of America
| | - Azadeh Bahmani
- Department of Physiology, Wayne State University, Detroit, MI 48201, United States of America
| | - Carrie L Turner
- LimnoTech, 501 Avis Dr., Ann Arbor, MI 48108, United States of America
| | - William Shuster
- Department of Civil and Environmental Engineering, Wayne State University, Detroit, MI 48202, United States of America
| | - Jeffrey L Ram
- Department of Physiology, Wayne State University, Detroit, MI 48201, United States of America; Department of Biochemistry, Microbiology, & Immunology, Wayne State University, Detroit, MI 48201, United States of America.
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2
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Fan W, Zhao L, Yu L, Zhou Y. Chip-based digital PCR as a direct quantification method for residual DNA in mRNA drugs. J Pharm Biomed Anal 2024; 238:115837. [PMID: 37952451 DOI: 10.1016/j.jpba.2023.115837] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/14/2023]
Abstract
Residual exogenous DNA, as common contaminants in biological products, must be monitored and removed to ensure safety. Digital PCR (dPCR) technology is widely applied in DNA quantitative analysis due to high specificity, sensitivity, absolute quantification, etc. Data support is relatively lacking in deciphering the dPCR technology application in residual DNA of mRNA drugs. The current study helped establish the dPCR methods corresponding to two different mRNA vaccines to detect the residual DNA template. The established dPCR methods have a wide linear range, good precision, accuracy, and specificity without being interfered with by encapsulating and demulsifying reagents. The method is simple, rapid, and sensitive which demonstrates that dPCR can directly quantitate other types of risky DNA in mRNA drugs accurately as well.
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Affiliation(s)
- Wenchao Fan
- Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, National Institutes for Food and Drug Control, No. 2, Tiantan Xili, Dongcheng District, Beijing 100050, China
| | - Lan Zhao
- Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, National Institutes for Food and Drug Control, No. 2, Tiantan Xili, Dongcheng District, Beijing 100050, China
| | - Lei Yu
- Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, National Institutes for Food and Drug Control, No. 2, Tiantan Xili, Dongcheng District, Beijing 100050, China
| | - Yong Zhou
- Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, National Institutes for Food and Drug Control, No. 2, Tiantan Xili, Dongcheng District, Beijing 100050, China.
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3
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Blue LE, Guan X, Joubert MK, Kuhns ST, Moore S, Semin DJ, Wikström M, Wypych J, Goudar CT. State-of-the-art and emerging trends in analytical approaches to pharmaceutical-product commercialization. Curr Opin Biotechnol 2022; 78:102800. [PMID: 36182871 DOI: 10.1016/j.copbio.2022.102800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 08/17/2022] [Accepted: 08/25/2022] [Indexed: 12/14/2022]
Abstract
The biopharmaceutical landscape continues to evolve rapidly, and associated modality complexity and the need to improve molecular understanding require concomitant advances in analytical approaches used to characterize and release the product. The Product Quality Attribute Assessment (PQAA) and Quality Target Product Profile (QTPP) frameworks help catalog and translate molecular understanding to process and product-design targets, thereby enabling reliable manufacturing of high-quality product. The analytical target profile forms the basis of identifying best-fit analytical methods for attribute measurement and continues to be successfully used to develop robust analytical methods for detailed product characterization as well as release and stability testing. Despite maturity across multiple testing platforms, advances continue to be made, several with the potential to alter testing paradigms. There is an increasing role for mass spectrometry beyond product characterization and into routine release testing as seen by the progress in multi-attribute methods and technologies, applications to aggregate measurement, the development of capillary zone electrophoresis (CZE) coupled with mass spectrometry (MS) and capillary isoelectric focusing (CIEF) with MS for measurement of glycans and charged species, respectively, and increased application to host cell protein measurement. Multitarget engaging multispecific modalities will drive advances in bioassay platforms and recent advances both in 1- and 2-D NMR approaches could make it the method of choice for characterizing higher-order structures. Additionally, rigorous understanding of raw material and container attributes is necessary to complement product understanding, and these collectively can enable robust supply of high-quality product to patients.
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Affiliation(s)
- Laura E Blue
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - Xiaoyan Guan
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - Marisa K Joubert
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - Scott T Kuhns
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - Stephanie Moore
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - David J Semin
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - Mats Wikström
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - Jette Wypych
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA
| | - Chetan T Goudar
- Attribute Sciences, Process Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA.
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4
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Brimble MA, Cheng PH, Winston SM, Reeves IL, Souquette A, Spence Y, Zhou J, Wang YD, Morton CL, Valentine M, Thomas PG, Nathwani AC, Gray JT, Davidoff AM. Preventing packaging of translatable P5-associated DNA contaminants in recombinant AAV vector preps. Mol Ther Methods Clin Dev 2022; 24:280-291. [PMID: 35211640 PMCID: PMC8829444 DOI: 10.1016/j.omtm.2022.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 01/16/2022] [Indexed: 11/25/2022]
Abstract
Recombinant adeno-associated virus (rAAV) vectors are increasingly being used for clinical gene transfer and have shown great potential for the treatment of several monogenic disorders. However, contaminant DNA from producer plasmids can be packaged into rAAV alongside the intended expression cassette-containing vector genome. The consequences of this are unknown. Our analysis of rAAV preps revealed abundant contaminant sequences upstream of the AAV replication (Rep) protein driving promoter, P5, on the Rep-Cap producer plasmid. Characterization of P5-associated contaminants after infection showed transfer, persistence, and transcriptional activity in AAV-transduced murine hepatocytes, in addition to in vitro evidence suggestive of integration. These contaminants can also be efficiently translated and immunogenic, revealing previously unrecognized side effects of rAAV-mediated gene transfer. P5-associated contaminant packaging and activity were independent of an inverted terminal repeat (ITR)-flanked vector genome. To prevent incorporation of these potentially harmful sequences, we constructed a modified P5-promoter (P5-HS), inserting a DNA spacer between an Rep binding site and an Rep nicking site in P5. This prevented upstream DNA contamination regardless of transgene or AAV serotype, while maintaining vector yield. Thus, we have constructed an rAAV production plasmid that improves vector purity and can be implemented across clinical rAAV applications. These findings represent new vector safety and production considerations for rAAV gene therapy.
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Affiliation(s)
- Mark A. Brimble
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Department of Haematology, University College London (UCL) Cancer Institute, London WC1E 6DD, UK
| | - Pei-Hsin Cheng
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Stephen M. Winston
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Graduate School of Biomedical Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Isaiah L. Reeves
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Graduate School of Biomedical Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Aisha Souquette
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Yunyu Spence
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Junfang Zhou
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Yong-Dong Wang
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Christopher L. Morton
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Marcus Valentine
- Cytogenetics Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Paul G. Thomas
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Amit C. Nathwani
- Department of Haematology, University College London (UCL) Cancer Institute, London WC1E 6DD, UK
- Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital, London NW3 2QG, UK
| | - John T. Gray
- Vertex Cell and Genetic Therapies, Vertex Pharmaceuticals, Boston, MA 02210, USA
| | - Andrew M. Davidoff
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Graduate School of Biomedical Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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5
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PCR-Based Analytical Methods for Quantification and Quality Control of Recombinant Adeno-Associated Viral Vector Preparations. Pharmaceuticals (Basel) 2021; 15:ph15010023. [PMID: 35056080 PMCID: PMC8779925 DOI: 10.3390/ph15010023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/17/2021] [Accepted: 12/22/2021] [Indexed: 11/17/2022] Open
Abstract
Recombinant adeno-associated viral vectors (rAAV) represent a gene therapy tool of ever-increasing importance. Their utilization as a delivery vehicle for gene replacement, silencing and editing, among other purposes, demonstrate considerable versatility. Emerging vector utilization in various experimental, preclinical and clinical applications establishes the necessity of producing and characterizing a wide variety of rAAV preparations. Critically important characteristics concerning quality control are rAAV titer quantification and the detection of impurities. Differences in rAAV constructs necessitate the development of highly standardized quantification assays to make direct comparisons of different preparations in terms of assembly or purification efficiency, as well as experimental or therapeutic dosages. The development of universal methods for impurities quantification is rather complicated, since variable production platforms are utilized for rAAV assembly. However, general agreements also should be achieved to address this issue. The majority of methods for rAAV quantification and quality control are based on PCR techniques. Despite the progress made, increasing evidence concerning high variability in titration assays indicates poor standardization of the methods undertaken to date. This review summarizes successes in the field of rAAV quality control and emphasizes ongoing challenges in PCR applications for rAAV characterization. General considerations regarding possible solutions are also provided.
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6
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Overview of analytics needed to support a robust gene therapy manufacturing process. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2021. [DOI: 10.1016/j.cobme.2021.100339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Green EA, Lee KH. Analytical methods to characterize recombinant adeno-associated virus vectors and the benefit of standardization and reference materials. Curr Opin Biotechnol 2021; 71:65-76. [PMID: 34273809 PMCID: PMC8530916 DOI: 10.1016/j.copbio.2021.06.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/26/2021] [Accepted: 06/28/2021] [Indexed: 12/18/2022]
Abstract
Recombinant adeno-associated virus (rAAV) is an increasingly important gene therapy vector, but its properties present unique challenges to critical quality attribute (CQA) identification and analytics development. Advances in, and ongoing hurdles to, characterizing rAAV proteins, nucleic acids, and vector potency are discussed in this review. For nucleic acids and vector potency, current analytical techniques for defined CQAs would benefit from further optimization, while for proteins, more complete characterization and mapping of properties to safety and efficacy is needed to finalize CQAs. The benefits of leveraging reference vectors to validate analytics and CQA ranges are also proposed. Once defined, CQA specifications can be used to establish target parameters for and inform the development of next generation rAAV processes.
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Affiliation(s)
- Erica A Green
- Department of Chemical and Biomolecular Engineering, University of Delaware, 590 Avenue 1743, Newark, DE 19713, USA
| | - Kelvin H Lee
- Department of Chemical and Biomolecular Engineering, University of Delaware, 590 Avenue 1743, Newark, DE 19713, USA.
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8
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Tustian AD, Bak H. Assessment of quality attributes for adeno-associated viral vectors. Biotechnol Bioeng 2021; 118:4186-4203. [PMID: 34309017 DOI: 10.1002/bit.27905] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 12/24/2022]
Abstract
There is a strong and growing interest in the development and production of gene therapy products, including those utilizing adeno-associated virus (AAV) particles. This is evident with the increase in the number of clinical trials and agency approvals for AAV therapeutics. As bioproduction of AAV viral vectors matures, a quality by design (QbD) approach to process development can aid in process robustness and product quality. Furthermore, it may become a regulatory expectation. The first step in any QbD approach is to determine what physical, chemical, biological, or microbiological property or characteristic product attributes should be controlled within an appropriate limit, range, or distribution to ensure the desired product quality. Then predefined goals are set to allow proactive process development to design in quality. This review lists typical quality attributes used for release testing of AAV viral vectors and discusses these and selected attributes important to extended characterization studies in terms of safety, efficacy, and impact upon the patient immune response.
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Affiliation(s)
| | - Hanne Bak
- Regeneron Pharmaceuticals Inc., Tarrytown, NY, USA
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9
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Gholizadeh-Hashjin A, Abedi N, Heidari HR, Lotfipour F. Direct quantitative detection of host cell residual DNA in recombinant Filgrastim by qPCR. Anal Biochem 2021; 629:114296. [PMID: 34216563 DOI: 10.1016/j.ab.2021.114296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/24/2021] [Accepted: 06/29/2021] [Indexed: 10/21/2022]
Abstract
Host cell residual DNA is considered as an impurity in recombinant biopharmaceuticals. This study aimed to develop a direct qPCR method to quantify E. Coli residual DNA in recombinant Filgrastim. The specific primers were designed to amplify E. Coli's 16S-rDNA genomic region, which encodes the 16S-rRNA. The developed qPCR method showed that the designed primer has specifically amplified the target genome without any secondary reaction. The designed primer was also able to amplify the target gene as a representative of residual DNA in the drug matrix. Results show that the amount of residual DNA in Filgrastim is undetectable.
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Affiliation(s)
| | - Nasim Abedi
- Student Research Committee, Tabriz University of Medical Sciences, Faculty of Pharmacy, Tabriz, Iran
| | - Hamid Reza Heidari
- Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzaneh Lotfipour
- Food & Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Pharmaceutical and Food Control, Tabriz University of Medical Sciences, Faculty of Pharmacy, Tabriz, Iran.
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10
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Rieser R, Koch J, Faccioli G, Richter K, Menzen T, Biel M, Winter G, Michalakis S. Comparison of Different Liquid Chromatography-Based Purification Strategies for Adeno-Associated Virus Vectors. Pharmaceutics 2021; 13:pharmaceutics13050748. [PMID: 34070226 PMCID: PMC8158740 DOI: 10.3390/pharmaceutics13050748] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 01/01/2023] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors have evolved as one of the most promising technologies for gene therapy due to their good safety profile, high transduction efficacy, and long-term gene expression in nondividing cells. rAAV-based gene therapy holds great promise for treating genetic disorders like inherited blindness, muscular atrophy, or bleeding disorders. There is a high demand for efficient and scalable production and purification methods for rAAVs. This is particularly true for the downstream purification methods. The current standard methods are based on multiple steps of gradient ultracentrifugation, which allow for the purification and enrichment of full rAAV particles, but the scale up of this method is challenging. Here, we explored fast, scalable, and universal liquid chromatography-based strategies for the purification of rAAVs. In contrast to the hydrophobic interaction chromatography (HIC), where a substantial amount of AAV was lost, the cation exchange chromatography (CEX) was performed robustly for multiple tested serotypes and resulted in a mixture of full and empty rAAVs with a good purity profile. For the used affinity chromatography (AC), a serotype dependence was observed. Anion exchange chromatography (AEX) worked well for the AAV8 serotype and achieved high levels of purification and a baseline separation of full and empty rAAVs. Depending on the AAV serotype, a combination of CEX and AEX or AC and AEX is recommended and holds promise for future translational projects that require highly pure and full particle-enriched rAAVs.
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Affiliation(s)
- Ruth Rieser
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany; (R.R.); (J.K.); (G.F.); (M.B.)
| | - Johanna Koch
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany; (R.R.); (J.K.); (G.F.); (M.B.)
| | - Greta Faccioli
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany; (R.R.); (J.K.); (G.F.); (M.B.)
| | - Klaus Richter
- Coriolis Pharma, Fraunhoferstr. 18 b, 82152 Martinsried, Germany; (K.R.); (T.M.)
| | - Tim Menzen
- Coriolis Pharma, Fraunhoferstr. 18 b, 82152 Martinsried, Germany; (K.R.); (T.M.)
| | - Martin Biel
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany; (R.R.); (J.K.); (G.F.); (M.B.)
| | - Gerhard Winter
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany; (R.R.); (J.K.); (G.F.); (M.B.)
- Correspondence: (G.W.); (S.M.)
| | - Stylianos Michalakis
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany; (R.R.); (J.K.); (G.F.); (M.B.)
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstr. 8, 80336 Munich, Germany
- Correspondence: (G.W.); (S.M.)
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11
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Wang Y, Menon N, Shen S, Feschenko M, Bergelson S. A qPCR Method for AAV Genome Titer with ddPCR-Level of Accuracy and Precision. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 19:341-346. [PMID: 33145370 PMCID: PMC7591332 DOI: 10.1016/j.omtm.2020.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/25/2020] [Indexed: 12/16/2022]
Abstract
Recombinant adeno-associated virus (rAAV) is one of the main vectors used in gene therapy. An accurate genome titer is not only critical for clinical dosing, but also a prerequisite for many analytical assays for AAV product characterization. AAV genome titer is traditionally determined by qPCR; however, assay precision is not optimal despite extensive efforts. More recently, droplet digital PCR (ddPCR) emerged as a powerful alternative that offers excellent accuracy and precision. However, currently ddPCR is not as widely available as qPCR and operates at a lower throughput and a higher cost. In this paper, we introduce an improved qPCR method with two major optimizations: (1) using an AAV reference material as qPCR standard instead of plasmid DNA and (2) implementing a “digestion-free” method by adding 5% Tween 20 to standard and sample preparations. The new method has been extensively tested with AAV of different serotypes, purification status, and transgenes encapsidated and was found to be highly accurate, precise, and robust. This significantly improved and simplified assay can be easily adopted by researchers in the gene therapy field and further automated for high-throughput applications.
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Affiliation(s)
- Yu Wang
- Department of Analytical Development, Biogen, Inc., 225 Binney Street, Cambridge, MA 02142, USA
| | - Namrata Menon
- Department of Analytical Development, Biogen, Inc., 225 Binney Street, Cambridge, MA 02142, USA
| | - Shen Shen
- Gene Therapy Accelerator Unit, Biogen, Inc., 225 Binney Street, Cambridge, MA 02142, USA
| | - Marina Feschenko
- Department of Analytical Development, Biogen, Inc., 225 Binney Street, Cambridge, MA 02142, USA
| | - Svetlana Bergelson
- Department of Analytical Development, Biogen, Inc., 225 Binney Street, Cambridge, MA 02142, USA
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12
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A novel method for removing polyethyleneimine from biopharmaceutical samples: improving assay sensitivity of residual DNA qPCR. Biotechniques 2020; 68:353-358. [PMID: 32228190 DOI: 10.2144/btn-2020-0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Polyethyleneimine (PEI) is a flocculent that is widely used in the downstream purification of monoclonal antibodies. It is an in-process residual that is carried through the drug purification process and strongly inhibits residual DNA quantitation by real-time quantitative PCR assay. Very high sample dilutions (e.g., 1:10,000) can overcome the interference of PEI, but at the cost of DNA assay sensitivity. Diluting samples poses a significant risk to the assay sensitivity needed to satisfy regulatory requirements on the quantitation of residual genomic DNA present per dose (i.e., 10 ng/dose). Removing PEI while retaining DNA, by the use of sodium dodecyl sulfate, heparin and/or sarkosyl can overcome the interference of PEI and allow a more accurate quantitation of residual DNA.
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13
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Moleirinho MG, Silva RJS, Alves PM, Carrondo MJT, Peixoto C. Current challenges in biotherapeutic particles manufacturing. Expert Opin Biol Ther 2019; 20:451-465. [PMID: 31773998 DOI: 10.1080/14712598.2020.1693541] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Introduction: The development of novel complex biotherapeutics led to new challenges in biopharmaceutical industry. The potential of these particles has been demonstrated by the approval of several products, in the different fields of gene therapy, oncolytic therapy, and tumor vaccines. However, their manufacturing still presents challenges related to the high dosages and purity required.Areas covered: The main challenges that biopharmaceutical industry faces today and the most recent developments in the manufacturing of different biotherapeutic particles are reported here. Several unit operations and downstream trains to purify virus, virus-like particles and extracellular vesicles are described. Innovations on the different purification steps are also highlighted with an eye on the implementation of continuous and integrated processes.Expert opinion: Manufacturing platforms that consist of a low number of unit operations, with higher-yielding processes and reduced costs will be highly appreciated by the industry. The pipeline of complex therapeutic particles is expanding and there is a clear need for advanced tools and manufacturing capacity. The use of single-use technologies, as well as continuous integrated operations, are gaining ground in the biopharmaceutical industry and should be supported by more accurate and faster analytical methods.
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Affiliation(s)
- Mafalda G Moleirinho
- IBET, Instituto de Biologia Experimental e Tecnológica, Apartado, Oeiras, Portugal.,ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Ricardo J S Silva
- IBET, Instituto de Biologia Experimental e Tecnológica, Apartado, Oeiras, Portugal
| | - Paula M Alves
- IBET, Instituto de Biologia Experimental e Tecnológica, Apartado, Oeiras, Portugal.,ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Manuel J T Carrondo
- IBET, Instituto de Biologia Experimental e Tecnológica, Apartado, Oeiras, Portugal
| | - Cristina Peixoto
- IBET, Instituto de Biologia Experimental e Tecnológica, Apartado, Oeiras, Portugal.,ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
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