Recombinant therapeutics, including gene and cell therapies and vaccines, are often contaminated with proteins from the host cell system from which they were produced. Called “host cell proteins” (HCPs), these process-related contaminants can co-purify along with the therapeutic protein and cause significant drug safety and efficacy problems. Host cell protein analysis, or HCP analysis, is required to ensure drug safety.
Prolytix Offers Integrated HCP Services With a Difference
Prolytix offers a unique and comprehensive approach to biopharmaceutical industry to solve HCP challenges. Using both high-resolution mass spectrometry (HRMS) and ELISA, Prolytix provides phase-appropriate methods for host cell protein analysis of biotherapeutic products from early development through full cGMP release testing.
The best time to implement HCP analysis by HRMS is during process development: Prevent HCP problems from happening versus trying to go back and fix them after the process has been “locked down.” At Prolytix, we have developed higher-throughput HRMS methods that can quickly and economically help companies purify their product protein.
Applicable Drug Substances
- Monoclonal antibodies (mAbs)
- Recombinant proteins: fusion proteins, chimeras, active enzymes, zymogens, etc.
- Gene therapies
- Vaccines
Why HCP Testing? It’s All About Drug Safety and Efficacy
HCPs can reduce drug efficacy (e.g., glycosidases, proteases, lipases), trigger immunologic responses in patients, or the biological activity of an HCP may cause an adverse event.
HCP Methods
There is no such thing as the “perfect HCP detection method.” Each has its own strengths and weaknesses, and so a combined approach is recommended. The core methods used today are HCP ELISA and mass spectrometry.
HCP ELISA
The HCP ELISA test is both the workhorse and gold standard in biopharma. Briefly, host cell proteins from a null cell line are injected into animals (goat, sheep, rabbit, etc.), and the antibodies generated against those HCPs are collected and purified and used in the ELISA. One of the main problems with this approach is that the HCP ELISA is immunologically weighted based on how those animals respond to the HCP antigens: Some HCPs may generate production of lots of antibodies, but some may generate little or none. The ELISA result is therefore not strictly quantitative on an HCP-by-HCP basis, and the actual HCP profile of a sample remains unknown.
Despite this and other weaknesses, the HCP ELISA has two advantages:
- (1) high throughput
- (2) the result is a simple single number that is conceptually easy (on the surface) to remember and use to track purification of the product.
Liquid Chromatography With Tandem Mass Spectrometry (LC-MS/MS)
The power of mass spectrometry is that it enables us to identify and quantify specific HCPs in samples. The proteins in a sample are digested into peptides, the peptides are separated by high-performance liquid chromatography (HPLC) and injected into a mass spectrometer. Tandem mass spectrometry (MS/MS) analysis and the subsequent data processing enables one to identify and quantify what HCPs are in a sample. This level of detail is critical for rationally designing a purification process and insuring against being surprised by safety or efficacy problems during clinical trials.
Preventing HCP Problems During Process Development
The best way to avoid HCP problems is to develop a robust process where the clearance of HCPs has been validated for each column. Mass spectrometry gives the process development team the clarity and detail needed to rationally design the purification method based on HCP identity, MW, pI, and concentration. Mass spectrometry enables the establishment of HCP clearance (on a protein-by-protein basis) at each step of the process.
At Prolytix, we have developed highly efficient LC-MS/MS workflows that can provide answers quickly and economically. We have honed these methods over the last decade, and we do not sacrifice quality and the stringency of data analysis. Our specialty is working with companies to rapidly diagnose their HCP problems so they can be solved. The days of relying on gels, blots, and ELISAs are nearing their end. Contact us to see how our advanced bioanalytical services can help you quickly overcome your HCP problems and start your clinical trials with a high-quality product.
The Rich History of Prolytix’s HCP Projects
Many of our HCP projects at Prolytix require creative problem-solving. We specialize in working with startup companies who do not have the resources for HCP ELISA and mass spectrometry analysis. We also work with companies when they are using a CDMO to develop the process, but the CDMO does not have the bandwidth to solve a particularly sticky HCP problem. We’ve also worked with companies with commercially licensed products, but who suddenly have an HCP problem show up.
In all these cases, we have seen over and over that complete reliance on traditional analytical biochemistry — or even HCP ELISAs — can be a dead end. Only mass spectrometry can provide the insight needed to diagnose the problem, and then help solve it.