Biologics and Bioassays
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Biologics and Bioassays

Biologics refers to a wide range of pharmaceutical products manufactured, extracted, or semi-synthesized from a biological source, including vaccines, allergens, tissues, somatic cells, whole blood, gene therapies, blood components, recombinant therapeutic proteins, etc.

Bioassay is an ideal analytical method for determining the potency and stability of drugs. It determines the concentration or potency of a substance by its effect on living animals or plants (in vivo) or living cells or tissues (in vitro). This assessment is usually achieved by comparing the response of the test substance with that of the reference substance, and can reflect the clinical mechanism of action of the drug.

Introduction of Biologics and Bioassays

Biologics are large complex molecules produced by microorganisms or mammalian cells, most of which are proteins or peptides. Muromonab CD3, the first monoclonal antibody, was approved in 1982 as a mouse protein for acute organ transplant rejection. A pioneering study at Cambridge University provided a way to reduce immunogenicity, leading to the production of the second monoclonal antibody, abciximab (1993), which has since ignited a revolution in protein engineering. Biotechnology continues to evolve, including adequate human antibodies and emerging technologies to enhance drug safety and efficacy.

A few examples of Biologics

Drug nameMechanism of actionIndication
AfliberceptVascular endothelial growth factor (VEGF)Wet macular degeneration, metastatic colorectal cancer
BevacizumabVascular endothelial growth factor A (VEGF-A)Colon cancer, lung cancer, glioblastoma, renal-cell carcinoma, eye disease
ErythropoietinStimulation of red blood cell productionAnemia arising from cancer chemotherapy, chronic renal failure
EtanerceptTNF antagonistRheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, psoriasis
InfliximabTNF antagonistRheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, psoriasis, ulcerative colitis, Crohn's disease
TrastuzumabHER2/neu (erbB2) antagonistBreast cancer
UstekinumabIL-12 and IL-23 antagonistPsoriatic arthritis, psoriasis, ulcerative colitis, Crohn's disease
Denileukin diftitoxInterleukin-2 receptor binderCutaneous T-cell lymphoma (CTCL)

Bioassays use biological indicators to measure the potency of living organisms or tissues. They can provide critical data on the potency and stability of a drug product and can provide evidence to confirm the biocomparability of innovative and biosimilar products. These can include cell-based tissue cultures, microarray expression technology, knockout animal models, transgenic animal models, and antisense or antibody technology (e.g., diagnostic antibody characterization). Some common bioassays include flow cytometry, proliferation, apoptosis, and functional reporter bioassays.

The Source of Biologics

  • Whole blood and other blood components
  • Organ transplantation and tissue transplants
  • Stem-cell therapy
  • Antibodies for passive immunity (e.g., to treat a virus infection)
  • Human reproductive cells
  • Human breast milk
  • Fecal microbiota

Classification of Biologics

  • Monoclonal antibodies
  • Enzyme substitutes or modulators
  • Cell-surface receptor function substitutes or modulators

Classification of Bioassays

  • Direct assay (the stimulus is specific and directly measurable, and the response is recorded)
  • Indirect assay (the stimulus is fixed in advance and the response is measured in the subjects)
    • Quantitative response (the response to the stimulus is measured continuously)
    • Quantal response (the response is binary)

Major kinds of Biologics

  • Blood factors (Factor VIII and Factor IX)
  • Thrombolytic agents (tissue plasminogen activator)
  • Hormones (insulin, glucagon, growth hormone, gonadotrophins, parathyroid hormone)
  • Haematopoietic growth factors (Erythropoietin, colony-stimulating factors)
  • Vaccines (Hepatitis B surface antigen)
  • Monoclonal antibodies (MAbs)
  • Interferons (Interferons-α, -β, -γ)
  • Interleukins (Interleukin-2)
  • Polypeptides
  • Proteins
  • Other products (tumour necrosis factor, therapeutic enzymes)

Advantages of Bioassays

  • Don't need time consuming culture cells, reduce the error of the work in the laboratory
  • Save time in the development and validation of the assay
  • Provide accurate and precise data with high reproducibility, high repeatability and stability
  • Reduce the costs
  • Simple operation, easy to run, fast speed, high efficiency, fast results
  • Facilitate simplified global method transfer and ultimately accelerate potency detection and QC lot release


BOC Sciences has a number of innovative technologies and platforms that can be used to help automate the bioassay testing process and improve greater throughput, speed, reliability and repeatability. BOC Sciences utilizes platforms (Flow Cytometry, ELISA, ProteinSimple ELLA, qPCR and MSD-ECLIA, etc.) to support the delivery of its bioassay services.

Biologics can be used in rheumatology, oncology, cardiology, dermatology, gastroenterology, neurology, and other fields. Biologics have increased the main therapeutic options for treating many diseases, including some for which there are no effective therapies and some for which previously existing therapies were inadequate. But biological therapies are much more expensive than conventional drugs, so biologics are used to treat chronic diseases such as rheumatoid arthritis or inflammatory bowel disease or to treat cancers that are incurable for the rest of life. In many ways, biologics are thought to be designed for patients with rare diseases or genetic subclasses of widespread diseases.


  1. Shire SJ. Formulation and manufacturability of biologics. Curr Opin Biotechnol. 2009 Dec; 20(6): 708-14.
  2. Kinch MS. An overview of FDA-approved biologics medicines. Drug Discov Today. 2015 Apr; 20(4): 393-8.
  3. Cairns J; et al. The scientific basis of bioassays. Hydrobiologia. 1989, 188-189(1): 5-20.