Cell Based Potency Assays

Biological activity must be confirmed for each lot of biopharmaceutical before releasing the lot for use and the most common method to confirm biological reactivity is by a cell based potency assay. Biologics that need to test for potency includes therapeutic antibodies (such as monoclonal antibodies, antibody drug conjugates, bispecific antibodies and Fab products), recombinant proteins and gene therapy products.  Some recombinant products, such as insulin and glucagon, have prescribed potency assays described in USP but novel products often require a potency assay to be developed from scratch.  PBL can work with you to find the best solution to your in vitro potency assays.

Types of In Vitro Bioassays

  • Binding Assays – If the mechanism of action requires the biopharmaceutical to bind to a receptor or a protein, that binding activity could be determined using an immunoassay such as ELISA.  An example in which a binding assay would be appropriate would be therapeutic monoclonal antibodies.
  • Enzyme Activity Assay – The potency of enzyme can be biochemically determined using an enzyme activity assay or biochemical assay.  Spectrophotometric, fluorometric, calorimetric, chemiluminescent and light scattering assays are all commonly used to detect enzyme activity.  An enzyme activity assay typically tests the activity of a single functional domain of the therapeutic product and, depending on the mode of action, the enzyme activity assay can be used in conjunction with a binding assay to show biological potency.
  • Cell Based Assays – Cell based assay are preferred when the biopharmaceutical contains multiple functional domains which will all need to be intact in order for the product to be effective.  For example, if the biopharmaceutical protein contains a membrane translocation domain and a transcription factor domain, a cell based assay would be able to show the activity of both functional domains, the transcription factor domain by using a reporter gene and the membrane translocation domain because the protein would need to be able to enter the cell to activate the gene.  Custom cell based assays could be developed by PBL depending on your needs.  The staff at PBL would be happy to discuss your product with you and help determine what type of cell based assay would work best for your product.

Types of Cell Based Assays

  • Cell Proliferation Assays – Products that induce cellular proliferation might be able to be tested for potency using various different cellular quantitative proliferation assays such as the MTT assay.  Products that may be able to utilize a cell proliferation assay to show biological activity are products used to treat neurodegenerative diseases, heart disease or wound healing.
  • Cell Death Assays –Biopharmaceuticals designed to target and kill certain cells could be tested for potency using an assay that quantitatively measures cell death such as the MTT assay.  An example of biopharmaceutical that triggers cell death is a protein used as a cancer therapy.
  • Reporter Gene Assays – A biopharmaceutical could activate a series of events leading to the expression of a reporter gene which can then be detected and correlated to the activity of the biopharmaceutical.  Engineered cell lines may need to be created or purchased but a wide range of biological products could be tested for potency by using a reporter gene to show biological activity.
  • Cell Signaling Assays – Biopharmaceuticals often activate a signaling cascade which results in a specific therapeutic effect.  A potency assay could be developed for your biopharmaceutical showing the increase or decrease of certain signaling molecules such as cAMP.

In Vitro Bioassay and Cell Based Assay Testing Services

  • Method Development – Our team of scientists can develop a custom in vitropotency assays specific for your biological product.  Pacific BioLabs will work with you to understand your product and development needs.
  • Method Validation in Accordance with ICH Guidelines – Pacific BioLabs can validate your in vitro bioassay following ICH requirements: accuracy, precision, linearity, range, specificity, LOD/LOQ, and robustness.
  • Method Optimization – Use PBL’s knowledge and experience to improve your bioassay.  Our team of scientists can work with you to figure out the best way to optimize your method.
  • Method Transfer – If you would like to perform the routine lot release testing within your own facility or at another testing lab, you can still utilize PBL’s method development and validation services and then PBL could transfer the method back to your lab complete with a transfer protocol.
  • Routine Lot Release Testing – Pacific BioLabs is a cGMP compliant laboratory and has over 30 years of experience supporting the pharmaceutical and medical device industries by performing a variety of different lot release tests on thousands of different products. Your lot release testing will be done right the first time at PBL.
  • Potency Testing  within a Stability Study – Potency testing may be a required component of your stability testing protocol.  To learn more about PBL’s stability testing capabilities please visit our stability testing webpage.


Read More About In Vitro Bioassays and Cell Based Assays

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