Occupational Exposure Risks When Working with Protein Therapeutics and the Development of a Biologics Banding System

An Industry Proposal for a Cell and Gene Therapy Safety Data Sheet

Introduction

A safety data sheet (SDS) is an established hazard communication tool for chemicals, for which no comparable document exists in the biotherapeutics industry. As the cell and gene therapy (CGT) field expands, industry leaders have identified a growing need to address this gap in communication of the unique occupational health and safety risks posed by CGT materials and products.

Methods

Following the sections of a traditional chemical SDS, information was modified by industry subject matter experts, relevant to CGT biological materials. This guide was developed based on assumptions of a maximum biosafety level 2, and any chemical components present in the material were excluded from the hazard classification.

Results

The guide contains necessary information to conduct a workplace risk assessment and communicate the unique workplace hazards posed by potential exposures to the material. The target audience is intended to be entities handling and producing these materials, plus collaborators, contractors, or operations sites receiving and handling the CGT material. An example of a CGT SDS is provided in Table 1.

Discussion

The CGT SDS provides industry with a best practice to address an existing gap in hazard communication for CGT. We expect that, as the field evolves, so may the contents. The CGT SDS can be used as a reference for other biological modalities in the field.

Conclusions

This initial CGT SDS communicates workplace hazards and assesses the unique risks posed by these biological materials and can assist in creating exposure control plans specific to the workplace hazards.

Estimating inhalation bioavailability for peptides and proteins 1 to 10 kDa in size

Inhalation is a critical route for occupational exposure. To protect workers from adverse effects, health-based exposure limits (HBELs) are derived using chemical-specific information including inhalation bioavailability. Inhalation bioavailability of large proteins is well studied and generally accepted to be 1% or less. However, the inhalation bioavailability of peptides and proteins 1-10 kDa in size is not well defined. The goal of this study was to expand upon previous analyses and evaluate the inhalation bioavailability of small peptides. Inhalation bioavailability data for 72 peptides and protein samples ranging from 1.1 to 10.9 kDa in size were evaluated. The median inhalation bioavailability was 20%, which is in agreement with previously published analyses. Inhalation bioavailabilities for the vast majority were below 50%. Interestingly, species, peptide size, and peptide identity did not correlate with inhalation bioavailability. Other factors including inhalation dosimetry, peptide degradation, and chemical characteristics also decrease the amount of peptide available for absorption. Together, the median bioavailability of 20% is likely an appropriate estimate of systemic exposure and is sufficiently protective in most cases for the purposes of occupational exposure safety. Thus, in the absence of peptide-specific data or concerns, an inhalation bioavailability default of 20% is recommended for 1-10 kDa peptide and proteins.

The utility of hERG channel inhibition data in the derivation of occupational exposure limits

Inhibition of the human ether-à-go-go (hERG) channel may lead to QT prolongation and fatal arrhythmia. While pharmaceutical drug candidates that exhibit potent hERG channel inhibition often fail early in development, many drugs with both cardiac and non-cardiac indications proceed to market. In this study, the relationship between in vitro hERG channel inhibition and published occupational exposure limit (OEL) was evaluated. A total of 23 cardiac drugs and 44 drugs with non-cardiac indications with published hERG channel IC₅₀ and published OELs were identified. There was an apparent relationship between hERG IC₅₀ potency and the OEL for cardiac and non-cardiac drugs. Twenty cardiac and non-cardiac drugs were identified that had a potent hERG IC₅₀ (≤25 μM) and a contrastingly large OEL value (≥100 μg/m³). OELs or hazard banding corresponding to ≤100 μg/m³ should be sufficiently protective of effects following occupational exposure to the majority of APIs with hERG IC₅₀ values ≤ 100 μM. It is important to consider hERG IC₅₀ values and possible cardiac effects when deriving OEL values for drugs, regardless of indication. These considerations may be particularly important early in the drug development process for establishing exposure control bands for drugs that do not yet have full clinical safety data.