Framework for sensitization assessment of extractables and leachables in pharmaceuticals

Cell and Gene Therapies: Challenges in Designing Extractables and Leachables Studies and Conducting Safety Assessments

Over the past decade, Cell and Gene Therapies (C>) have been an emerging therapeutic area with more than twenty C> drug products approved and over 1000 registered trials. The remarkable progress in these modalities brings new challenges for scientists who evaluate manufacturing and storage materials, including risk assessments for extractables and leachables (E&L). Establishing a business process to qualify materials for these applications is an important risk mitigation strategy in support of these assessments. Process validation verifying process performance and product quality requirements using qualified materials also ensures that leachables from the materials do not result in an impact to process and product. The authors provide an overview of available guidelines and publications relevant to E&L risk assessments that can be used to support ex vivo C> products, highlighting gaps and standardization needs in the areas of biocompatibility and extractables conditions. Finally, the authors present leachable testing strategies, relevant to the specific manufacturing and storage conditions of C> products, and safety assessment considerations for organic and inorganic chemical entities.

Antibody-Drug Conjugate Overview: a State-of-the-art Manufacturing Process and Control Strategy

Antibody-drug conjugates (ADCs) comprise an antibody, linker, and drug, which direct their highly potent small molecule drugs to target tumor cells via specific binding between the antibody and surface antigens. The antibody, linker, and drug should be properly designed or selected to achieve the desired efficacy while minimizing off-target toxicity. With a unique and complex structure, there is inherent heterogeneity introduced by product-related variations and the manufacturing process. Here this review primarily covers recent key advances in ADC history, clinical development status, molecule design, manufacturing processes, and quality control. The manufacturing process, especially the conjugation process, should be carefully developed, characterized, validated, and controlled throughout its lifecycle. Quality control is another key element to ensure product quality and patient safety. A patient-centric strategy has been well recognized and adopted by the pharmaceutical industry for therapeutic proteins, and has been successfully implemented for ADCs as well, to ensure that ADC products maintain their quality until the end of their shelf life. Deep product understanding and process knowledge defines attribute testing strategies (ATS). Quality by design (QbD) is a powerful approach for process and product development, and for defining an overall control strategy. Finally, we summarize the current challenges on ADC development and provide some perspectives that may help to give related directions and trigger more cross-functional research to surmount those challenges.

Semiquantitative sensitization safety assessment of extractable and leachables associated with parenteral pharmaceutical products

Extractable and leachables (E&Ls) associated with parenteral pharmaceutical products should be assessed for patient safety. One essential safety endpoint is local or systemic sensitization. However, there are no regulatory guidelines for quantitative sensitization safety assessment of E&Ls. A semiquantitative sensitization safety assessment workflow is developed to refine the sensitization safety assessment of E&Ls associated with parenteral pharmaceutical products. The workflow is composed of two sequential steps: local skin sensitization and systemic sensitization safety assessment. The local skin sensitization step has four tiers. The output from this step is the acceptable exposure level for local sensitization (AEL_ls) and this safety threshold can be used for local sensitization safety assessment. From the derived AEL_ls, the systemic sensitization safety assessment at step 2 proceeds in 2 tiers. The output from this workflow is the derivation of acceptable exposure level for systemic sensitization (AEL_ss). When the estimated human daily exposure (HDE) is compared with the AEL_ss, the margin of exposure is calculated to determine the sensitization safety of E&Ls following parenteral administration. The current work represents an initial effort to develop a scientifically robust process for sensitization safety assessment of E&Ls associated with parenteral pharmaceutical products.

A case study: Re-evaluating the biological risk following a processing aid change on a marketed cardiovascular implant device

Per ISO 10993-1:2018, a processing change to a medical device requires re-evaluation of biological risk. Here, we present the biological evaluation of a marketed cardiovascular implant following a detergent formulation change. This change was initially assessed through a qualitative toxicological risk assessment based on the fully disclosed detergent formulation and a limited panel of biological testing. The conclusion was that the new detergent did not impact the biological safety of the device. This assessment was rejected during regulatory review, and extractables and leachables under exhaustive extraction conditions were then evaluated for devices processed with new versus original detergent. New extractables were present at low levels (2–65 µg/device), and a toxicological risk assessment concluded no concern. The regulatory agency responded requesting additional biological testing to evaluate local effects, further characterization of compounds with a “tentative” identification, and leachable data to support clinically relevant exposure estimates. All additional data was collected per the agency request. Still, the conclusion, considering all data, was unchanged, suggesting the extensive chemical characterization and repeat biological testing unnecessary, especially considering animal use. This case study highlights the recent shift in regulatory expectations around chemical characterization and questions the value of additional biological testing when faced with low extractable levels of low toxicity concern. It also demonstrates the need to hold to key portions of the ISO 10993 risk management framework to avoid excessive burden on medical device development when there is little to no determined risk to patient safety.