Tech Briefing: HCP ELISAs for Gene Therapy Products

Over the years we’ve heard more complaints about HCP ELISAs from gene and cell therapy folks than anyone else. Many of the developmental efforts have been performed in more academic or translational research environments, where the regulatory requirements of HCP analysis were not always front-and-center in the product development pathway. As a result, HCP analysis was often done late in the development process and was considered more of a check-the-box effort. Very few of these groups had the resources to develop their own HCP ELISA, so they relied on commercial kits. Many of these products are produced in HEK293 cell lines, and there are limited options for commercial HEK293 HCP ELISA kits. Thus, limited consumer choice has been another reason for the complaints. Compounding this, many in the gene therapy field are not aware of the limitations of using a commercial HCP ELISA kit. When the kit vendor changes reagent lots or does a wholesale change/upgrade of the kit, they are left wondering how to cope with HCP ELISA results that can change by as much as three-fold.

Tech Briefing: Ins and Outs of Data Analysis for Potency Calculations

More than any other analytical method in the biopharmaceutical industry, the potency assay requires a in-depth knowledge of statistics. Most potency assays are cell-based relative potency assays. The readout is quantitative and requires assessing similarity of reference vs. test sample dose-response curves. Just to set up the data analysis, one must understand modeling and determination of similarity of dose response curves for reference material and test samples. Most analytical scientists have taken a college class (or maybe two) of applied statistics. This means that most of us know how to calculate averages, means and medians, and perhaps even calculate the confidence interval of these datasets.

Synopsis: BEBPA’s 2023 Host Cell Protein Conference in Review

Volume 1, Issue 2: Dr. Denise Krawitz provided an excellent wrap up on the last day of BEBPA’s 11th Annual HCP Conference held in May 2023 in Dubrovnik, Croatia. Her quick 10-minute summary captured the essence of the conference and highlighted topics covered during the conference, as well as providing a sneak peek into future topics.

Tech Briefing: Mass Spectrometry In HCP Analysis (USP 1132.1)

Host Cell Protein (HCP) analysis by mass spectrometry (LC-MS/MS) has obviously been growing in importance in the last decade. However, LC-MS/MS analysis is generally used for characterization, so the practitioners have been on their own to develop methods that work for their particular applications. HCP analysis has unique challenges that make it different from the MS-based general proteomics or characterization workflows that dominate the biotech and biopharma landscape. In HCP analysis, the analyst is trying to detect parts-per-million level peptides in a vast ocean of drug product (DP) peptides.

Tech Briefing: FDA Guidances for Assessing and Assuring the Potency of Cell and Gene Therapy Products

The FDA has two guidances about the potency of Cell and Gene Therapies (CGT). The most recent was released December 2023 entitled Potency Assurance for Cellular and Gene Therapy Products Draft Guidance for Industry. The older guidance entitled Guidance for Industry Potency Tests for Cellular and Gene Therapy Products has been around since 2011.

Tech Briefing: Working with Host Cell Proteins

Host cell proteins (HCPs) are a complex and diverse group of proteins produced by the cells used in biopharmaceutical manufacturing processes. We’d like to think that analytical methods used for release of a biopharmaceutical product are unambiguous – i.e., methods having well-defined target analyte(s), complete analyte coverage, high specificity, and a high degree of confidence in the results. The HCP ELISA, which is often used as a release assay, barely has any of those desirable traits. So, what other methods can we use to assess the purity of products? Outside of other immunoassays, mass spectrometry (LC-MS/MS) is most used. However, despite all the high-tech features of this method, it also is imperfect, especially when it comes to being a release assay.