Search

Cell and gene therapies have demonstrated impressive therapeutic efficacy in various human diseases. Nevertheless, cellular immune response directed against these therapeutic agents is an obstacle for achieving long-lasting clinical efficacy. Therefore, it is crucial to develop robust assays to accurately monitor cellular immunogenicity towards these therapies. Enzyme-linked immunospot (ELISpot) assay is one of the primarily used methods for measuring cellular immune response in clinical programs, which requires isolation of the peripheral blood mononuclear cells (PBMCs). The quality of this clinical material is one of the most critical factors that impact the robust assessment of cellular immune responses. The optimal blood sample processing conditions, however, remain poorly understood. In this study, we examined the impact of blood sample processing time on the performance characteristics of ELISpot to measure antigen-specific cellular responses. Blood samples that were processed after overnight delay resulted in a loss of ELISpot signals. We subsequently optimized several parameters of sample processing, and successfully recovered ELISpot signals for the blood samples that are processed within 32 h. Furthermore, several mitigation strategies were employed that would potentially address the impact of granulocyte contamination on detection of antigen-specific cellular responses. Our investigation provides an extension of sample processing window for clinical studies and is significant for resolving the logistical challenge of whole blood sample shipment for timely PBMC preparation in cell/gene therapy clinical studies., (© 2023. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Interest and efforts to use recombinant adeno-associated viruses (AAV) as gene therapy delivery tools to treat disease have grown exponentially. However, gaps in understanding of the pharmacokinetics/pharmacodynamics (PK/PD) and disposition of this modality exist. This position paper comes from the Novel Modalities Working Group (WG), part of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ). The pan-industry WG effort focuses on the nonclinical PK and clinical pharmacology aspects of AAV gene therapy and related bioanalytical considerations.Traditional PK concepts are generally not applicable to AAV-based therapies due to the inherent complexity of a transgene-carrying viral vector, and the multiple steps and analytes involved in cell transduction and transgene-derived protein expression. Therefore, we explain PK concepts of biodistribution of AAV-based therapies and place key terminologies related to drug exposure and PD in the proper context. Factors affecting biodistribution are presented in detail, and guidelines are provided to design nonclinical studies to enable a stage-gated progression to Phase 1 testing. The nonclinical and clinical utility of transgene DNA, mRNA, and protein analytes are discussed with bioanalytical strategies to measure these analytes. The pros and cons of qPCR vs. ddPCR technologies for DNA/RNA measurement and qualitative vs. quantitative methods for transgene-derived protein are also presented. Last, best practices and recommendations for use of clinical and nonclinical data to project human dose and response are discussed. Together, the manuscript provides a holistic framework to discuss evolving concepts of PK/PD modeling, bioanalytical technologies, and clinical dose selection in gene therapy., (© 2023. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Oligonucleotide therapeutics (ONTs) are a diverse group of short synthetic nucleic acid-based molecules that exploit innovative intracellular molecular strategies to create novel treatments for a variety of medical conditions. ONT molecules (~7-15 kDa) reside between traditional large and small molecules, and there has been debate regarding their immunogenicity risk. To date, 13 ON drugs have been approved, and as the field is relatively new, there are currently no specific regulatory guidelines to indicate how to develop, validate, and interpret the immunogenicity assays of ONTs. Some investigators do not test for immune responses to ONs while others test for antibodies (Abs) to components within the formulation, which may or may not include aspects of characterization such as domain mapping of ONT conjugates. Similar to other biopharmaceuticals, the immunogenic properties of ONTs could be influenced by sequence, route, dosage, target population, co-medications, etc. The current anti-drug antibody (ADA) data for different approved ONTs suggest that their administration poses a low immunogenicity risk without any significant impact on pharmacokinetics (PK), pharmacodynamics (PD), and safety; nevertheless, until the field matures with data from many more ON drugs, it remains prudent to assess immunogenicity. The emphasis of this article is to highlight how current ADA methodologies might be applied to the development of ONTs, discuss factors that may pose immunogenicity risks, and provide the authors' current position on immunogenicity assessment strategies for ONTs. We also discuss assay parameters that may be appropriate for the detection and characterization of ADAs, including the evaluation of neutralizing ADAs, ADA isotyping, Abs to dsDNA, and pre-existing ADA. Immunogenicity risk assessments (IRAs) and early interactions with regulators will inform how to proceed in late stage/pivotal studies., (© 2022. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Ligand binding assays (LBAs) have been the method of choice for protein analyte measurements for more than four decades. Over the years, LBA methods have improved in sensitivity and achieved larger dynamic ranges by using alternative detection systems and new technologies. As a consequence, the landscape and application of immunoassay platforms has changed dramatically. The introduction of bead-based methods, coupled with single molecule detection standardization and the ability to amplify assay signals, has improved the sensitivity of many immunoassays, in some cases by several logs of magnitude. Three promising immunoassay platforms are described in this article: Single Molecule Counting (SMC™) from Singulex Inc, Single Molecule Arrays (Simoa™) from Quanterix Corporation, and Immuno-PCR (Imperacer®) from Chimera Biotec GmbH. These platforms have the potential to significantly improve immunoassay sensitivity and thereby address the bioanalytical needs and challenges faced during biopharmaceutical drug development.

A parallel study design with a large number of subjects has been a typical path for pharmacokinetic (PK) biocomparability assessment of biotherapeutics with long half-lives and immunogenic propensity, for example, monoclonal antibodies (mAb). A recently published innovative bioanalytical method that can quantify mAb produced from two different cell lines in the same sample opened an avenue to exploring a simultaneous crossover study design for PK biocomparability assessment of biotherapeutics. Siltuximab, a chimeric IgG1 mAb-targeting interleukin-6, was studied as an example. The pharmacokinetic biocomparability of siltuximab derived from mouse myeloma (Sp2/0) cells and Chinese hamster ovary cells was previously assessed and demonstrated in a clinical PK biocomparability study that enrolled more than 140 healthy subjects using a parallel trial design. The biocomparability was successfully shown in six cynomolgus monkeys in a preclinical proof-of-concept study using the new crossover study design supported by the analytical method. The impact of antidrug antibodies on the assessment of biocomparability was minimal. This novel approach opened up a new arena for the evaluation of PK biocomparability of biotherapeutics with unique molecular signatures such as a mAb derived from different cell lines.