Trends, challenges and priorities

The EHS and biosafety team focuses on the safety of personnel when working with CGT processes at scale. This encompasses those in Research and Development (R&D) as well as those in traditional manufacturing roles. The term personnel includes support functions (quality assurance, site safety, engineering, etc.), as well as personnel who may require access to site, e.g. emergency responders and local physicians. It does not include patient safety.

Cell Risk Assessment

The current team is focused on the development and manufacturing stages, up to and including the supply of materials for clinical trials. Following the publication of the Environmental health and biosafety risk assessment framework for commercial-scale cell and gene therapy manufacturing and template, a Cells Risk Assessment sub-team was formed. The team has published the first in a series of case studies where the risk assessment is applied to real-world examples to stress-test the risk assessment, offer future improvements and provide a resource pack for the EHS worker.

This first paper, called Risk assessment of cells used in early development, explores early generation of cell banks. The focus is now the tech transfer from R&D/early development into a GMP manufacturing environment and how that affects the risk mitigations needed.

CGT EHS Resources

The EHS Resources sub-team has a long term goal of forming a dynamic website that contains resources for the EHS professional. The current focus of the team is safety data sheets. The current format is well suited to chemicals but is less appropriate for CGT products and intermediates. The team is sharing its experiences of the use and content of safety data sheets, and will publish a consensus template sheet with text to help the user early in 2022.

Approaches to Improve Methods

Clinical dose determination of AAV requires exact quantification and relies on accurate analytical measurements of vector genome copies for rAAV titration. Following survey findings (June 2020), dPCR may offer improvements in precision and accuracy over traditional qPCR platforms. To more robustly inform industry of the potential benefits of dPCR to measure vector genome copies, the Approaches to Improve Methods sub-team will collaborate on a platform comparison study initating October 2022 referring to a common protocol developed by the team. Following the study, the team will collate and present the study data in a future  paper.

Phase-Appropriate Approach to Assay Validation

Members of the Phase-Appropriate Approach to Assay Validation sub-team are developing an initial general paper that is aimed at promoting alignment on a common and compliant, phase-appropriate approach to assay validation relevant for CQAs of the most prevalent CGT modalities that will help promote a more efficient pathway towards each stage of filling.

Next-Generation Sequencing

Next-generation sequencing (NGS) has revolutionized genomic research, although its adoption in the manufacture of therapies has been slow. Challenges to its adoption arise from a lack of current regulatory guidance on the use of NGS for CGT applications and difficulties when validating a GMP-compliant method. This difficulty also stems from the complexity of implementing an NGS workflow that requires end-to-end validation of wet-laboratory assays, automation and sequencing instrumentation and the supporting software analysis pipeline. A core team of members of the Next Generation Sequencing sub-team are drawing on their collective experience to develop an introductory paper that will illustrate NGS workflows suitable for identity testing (viral vector identity). The paper content will be enriched by regularly engaging with the interested wider group for a series of discussion sessions / Q&A.

Empty/Full Capsids

A new, dedicated sub-team was established by High Level Analytics members in August 2021 in response to growing interest to increase understanding of empty/full capsids testing strategy. The Empty / Full Capsids sub-team are initially developing a comprehensive benchmarking survey that will consider vector agnostic, general questions focussed on gaining an understanding of how industry defines empty and partially full capsids as well as AAV and LVV dedicated sections which will explore vector – specific testing strategies. The survey outcome will determine the team’s next steps. Finally testing strategies for other process-related impurities (e.g. host cell DNA and plasmid DNA) as well as replication competent testing are being progressed via monthly workstream calls and benchmarking surveys.

Endonucleases

This sub-team aims to resolve technical issues and identify opportunities for improvement of endonucleases standards and specifications. A gap analysis of current standards has identified an opportunity to include an endonuclease best practice and/or specific validated standard to cover specific testing methods. The team aims to develop an industry stimulus article to propose a common, standardized approach for testing of endonucleases where they are used as a raw material in CGT product manufacturing. The plan for publication is early 2023.

Transfection Reagents

The subteam has identified common issues with transfection reagents with issues identified include certificate of analysis (CoA), drug master file, testing and quality biomanufacturing issues. Working with suppliers the team aims to develop improved alignment and a best practice, standardized approach to provide aligned benefits to both parties.

Apheresis

The sub-team aims to fully understand the challenges of the industry pain points with apheresis products from the initial collection, processing through to the end-user.

A detailed survey has been completed with focus areas including the tests needed to characterize apheresis products, patient data required by different processes, transportation of apheresis products and managing relationships and standardisation with the cell collection centres. The team are currently working on identifying common CGT industry specification attributes needed for both autologous and allogeneic apheresis collections, alongside vendor approval process of apheresis centre.

Supply Issues

This subteam’s aim is to look at the technical and quality supply issues within CGT raw materials. It is not focused on the long-range planning, forecast, and delivery of raw materials unless it is specifically CGT aligned and not covered within BioPhorum Supply Partner.

This program of work is a collaboration between two Phorums:

1. Cell and Gene Therapy Phorum – Raw Materials work stream – Supply Issues Cell & Gene Therapy sub team;
2. Supply Partner Phorum – Supply Chain Management for Cell & Gene Therapy workstream.

The team aim to deliver two topics,  an article to provide greater clarity on definition and Grade of materials for CGT,  especially where there is significant difference / challenges to that of drug products.  The second topic is to produce a stimulus article, set of templates and a webinar series to support Biomanufacturer understanding of supply chain process.

A function of this workstream is to provide regulatory support to the CGT technical teams and provides a forum where members share regulatory intelligence; track and stay aware of new guidance/industry standards and as well as activities that may be in progress by other external groups. During regular workstream calls, members consider and provide regulatory feedback to member questions received via Ask BioPhorum as well as offering regulatory input to CGT technical sub-teams when this would be valued to accelerate sub-team progress. By sharing knowlege and experiences, individual learnings may benefit all. Furthermore, whenever new CGT guidance is published, members will consider opportunities to review and discuss guidance to be aligned on interpretation and provide comments where possible.

This is evidenced by the formation of five separate review groups so far this year, who have collated and returned commentary on draft FDA, WHO and EQDM guidance/regulations during the public consultation periods.

Regulatory filing

1. The Regulatory Filing sub-team was launched as the start of 2022. The team are currently working on two deliverables.
   The team have collated a number of case studies of interactions with Health Authorities when preparing CGT submissions, currently focusing on viral vectors (AAV), CAR-T, gene modified (allogeneic). However, due to limited experience to share at this time, the information collated to date is to be published as a BioPhorum members only publication. The intention is to review the publication on a 6-monthly basis and update it to reflect additional case studies as experience with CGT submissions increases.
2. Technical issues when preparing CGT regulatory dossiers with regard to the CDT Module 3 are a common problem, with inconsistencies between regional requirements and a lack for regulatory guidance for CGT products. The sub-team aims to generate phase appropriate guidance and industry best practice addressing what technical information goes where in Module 3 CMC sections, with the regional differences.

Comparability

Demonstrating comparability presents some unique challenges for CGT developers owing to, for example, fast-tracked chemistry, manufacturing and controls (CMC) development, limited patient clinical data, batches and number of batches, and commercialization may require process transfer. Furthermore, regulatory guidelines on CGT product comparability across regions are vague, leading to a diversity of practice. CMC changes are expected and inevitable, particularly during early development, and this cross – workstream  subteam is aiming to document regulatory requirements as well as to provide recommendations on key considerations to help guide an appropriate rigor for comparability studies that is comensurate with timing of where change may ocur during product life cycle. A future article is planned and targeted for publication in 2022.
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RNA CQAs and Assays

An analytical focused sub-team prioritizing challenges around CQAs and Assays for RNA products. This sub-team has identified 2 specific lists of challenges/activities to be discussed, focusing on CQAs and on Assays. These are documented within their charter, although their first priority has been to map the existing landscape of literature and guidance relating to RNA analytics to help prioritize the challenges to address by identifying existing gaps in knowledge. This ‘mapping the landscape’ activity has created a growing list (currently 26) of documents as a reference that will help members in RNA analytical challenges.

The sub-team has also reviewed in-depth a WHO guidance to stimulate further discussion around RNA analytical challenges and generate further topic ideas; and the sub-team has also performed a journal article review to further expand awareness of the challenges to be addressed by the team.  This sub-team is now working towards its next deliverable of creating a CQA & Assays table detailing the what, why, where, when and how for RNA product attributes, which will eventually form the basis of an article for publication.

The team hopes this comprehensive CQAs and Assays table for mRNA/LNP drug can be used as a benchmarking tool for the industry. Companies can use the table to identify which CQAs to include during process and product development, as well as identify the importance, regulatory precedence and the different assay methods for each CQA.

CDMOs and CROs supporting RNA production/ manufacturing

Upon defining the sub-team charter and action list the team progressed their first activity of identifying transfer considerations that are unique to RNA products which could result in delays to a product transfer between a developer/sponsor and a contract organization. The team has converted this into a set of slides that companies will be able to use as a checklist during an NPI meeting to highlight and pre-empt potential issues unique to RNA products. 

The team decided to leverage the article and convert those considerations into a questionnaire to help ensure all critical RNA considerations are covered during initial sponsor-CDMO/CRO discussions.​ Organisations can use the questionnaire as a starting point for building their own questionnaire and adapting questions that are relevant to each project.​  Additionally, the questionnaire includes questions from the CDMO/CTO organization perspective for the Sponsor/developer, to ensure the product has the suitable development and background for a smooth transfer (provide clear indication of requirements).

Scale-up Challenges for RNA Drug Substance and RNA Drug Product Manufacturing

Following establishing a sub-team charter and list of scale-up challenges for RNA manufacture, the team have initially focused on creating a series of mRNA manufacture process flows (mRNA/LNP DP) to establish a common frame of reference for ongoing team discussions. In addition to providing a tool to facilitate future discussion and remove the ‘it-depends on the process’ comment when discussing scale-up challenges, the process flows will be a useful educational resource for members new to mRNA manufacture.  The team has also added descriptive text for all the key process steps and are now in the process of converting this content into a short article with the aim to publish this content on the BioPhorum website before progressing in-depth discussions on the list of scale up challenges identified.

Validation Templates

The subteam are working towards generating CGT specific templates for validation activities. The currently available templates can often be unsuitable for CGT products as they tend to be based on general biologics, which is at a different level of maturity to CGT. This can often result in additional work for the CGT user who may be required to complete irrelevant sections or provide unnecessary justifications as to why sections are incomplete. The team will generate usable templates specific for CGT products, with clear instructions that can be easily adaptable for use. The team are currently working towards generating a process performance master plan (PPQMP) template and plan to prepare templates for risk assessment, comparability and development activities.

Viral Clearance

A sub-team focusing on the unique challenges and possible options for viral clearance within CGT; taking into consideration that the introduction of a viral vector is often a key component of for a CGT product. The team are working towards a paper that will highlight the challenges, map the current regulatory landscape and propose potential solutions associated with viral clearance in this field. The principal focus of the publication will be on AAV gene therapies. However, the team will touch on other modalities where viral clearance may be a challenge (i.e. LVV, Cell Therapies) and discuss other approaches to control strategy that may be necessary. The publication will also include a section that will address relevant information contained within the recent ICHQ5A R2.

CGT Leveraging Process Data to accelerate validation

In developing gene therapy products using a transfection process, the only major change from product to product may be the gene of interest plasmid used. However, there is a requirement to conduct process characterization specifically for each product. This newly formed subteam will investigate if process characterization data can be leveraged across multiple products to accelerate validation timelines. The team will establish if a platform approach is possible for CGT and define what constitutes a robust platform process. The goal of the team is to generate an article detailing regulatory requirements, challenges and potential solutions for CGT process characterization and platform approaches. They will also detail a ‘best-practice’ approach to leverage process characterization data with a view to accelerating validation and generate a mock-case study to demonstrate this.

CGT Method Validation controls

Small batch sizes and limited material can often mean securing sufficient reference standard quantities for CGT can prove challenging. Lack of CGT specific guidance and standards around this topic further adds to the challenges for CGT products. This subteam will look to create a resource that provides recommendations around phase appropriate analytical controls across an number of attributes for both cell and gene therapies. Suggestions will also be made on (i) alternative sources of material when ideal controls are not available and (ii) how changes in processes may impact on analytical control requirements.