Biological Payloads

Biological Payloads

ADC structure

BOC Sciences can develop a variety of forms of payload, including protein, DNA, RNA, and a variety of other fragment technologies. An antibody-drug conjugate (ADC) connects a biologically active small molecule drug to a monoclonal antibody via a chemical link, and the monoclonal antibody acts as a carrier to target small molecule drugs to target cells. Effective payloads should be highly pharmacological and non-immunogenic, which is especially important in cancer treatment. Because the cytotoxic drugs used often interfere with the regulatory mechanisms of all cells in the body, leading to side effects such as impaired immune defense function, hair loss and nausea. Therefore, the best way to treat is to introduce the loaded toxic drug directly into the tumor cells before eliciting cytotoxic effects.

The toxins used as payloads should be soluble, easy to combine and stable. In order to trigger cytotoxic effects, payloads should have the following complex characteristics:

  • They must be highly cytotoxic. 
  • The target must be within the unit; and the molecular structure must be small to reduce the risk of immunogenicity.

According to the mode of action, the cytotoxin payloads in clinical trials can be divided into three categories: anti mitosis (tubulin filament damage), DNA damage or transcriptional inhibitors.

The payloads that BOC Sciences can produce include

  • Protein toxin

Small molecule (natural product) toxins are the main category of ADCs that have been approved for treatment or in clinical trials, accounting for 70% of the market. A protein toxin conjugated to an anti-tumor antibody to produce a fusion protein is a successful biopharmaceutical.

  • Pseudomonas exotoxin
  • Shiga toxin, Shiga-like toxin
  • Diphtheria toxin
  • Phytotoxins such as cholera toxins,
  • Toxins targeting tubulin filaments
  • Toxins Targeting DNA

DNA damage agents play an important role in cancer chemotherapy. Many DNA damage agents have been used in ADC research and development.

  • Caithromycin
  • CC-1065 analog
  • Docamycin
  • Toxins Targeting RNA

RNA polymerase can control cell growth and differentiation, and inhibit its activity can lead to apoptosis.

  • Amatosin
  • α-amanitin

In addition, BOC Sciences also provides antibody-directed enzyme prodrug therapy (ADEPT), which uses antibody-enzyme conjugates to achieve selective tumor cell death.

Our advantages

  • True loyalty and partnership
  • Skilled chemistry team
  • Fully equipped analytical support
  • High quality, low cost products
  • Advanced technology and methods
  • Comprehensive analysis of biopharmaceutical services


  1. Mariathasan, S. & Tan, M. W. Antibody–antibiotic conjugates: a novel therapeutic platform against bacterial infections. Trends in Molecular Medicine. 2017; 23(2):135-149.
  2. Kurt R. Gehlsen. Chapter 20: protein toxins as antibody–drug conjugate (adc) payloads. From the book: cytotoxic Payloads for Antibody-Drug Conjugates.
* Only for research. Not suitable for any diagnostic or therapeutic use.

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