Feasibility studies


PX'Therapeutics supports its customers from the early stages of their projects. From protein engineering to production of first batches for activity testing or proof-of-concept studies, we advise our customer based on our expertise and propose customised feasibility study programmes according to your specific needs.


We can assist you with:


Designing the candidate

  • Protein Engineering

Optimisation of challenging protein properties such as activity, affinity, stability and expression level.

Modification of antibody sequence to increase stability, limit aggregation or reduce immunogenicity.

  • Molecular Biology

Optimisation of gene sequence for expression in selected host, gene synthesis, mutagenesis and cloning.



Choosing the best expression strategy

  • Screening of multiple expression systems: bacteria, yeasts and mammalian cells.

    • For bacteria (E.coli): assessment of strains, vectors, expression location (periplasmic or cytoplasmic), medium.

    • For yeast: assessment of several strains of yeast, inducible or constitutive expression.

    • For mammalian cells: assessment of several cell lines, stable pool development using classical methods, transduction with lentiviral vectors (constitutive or inducible) for difficult-to-express or toxic proteins.



Setting up the production process

  • Upstream process

Set-up of culture and production protocols to maximise protein quality and yield

  •  Downstream process

Design of optimal purification schemes using affinity, ion exchange, hydrophobic interaction, mixed-mode and size-exclusion chromatographies.

Specific expertise for proteins expressed in inclusion bodies in E. coli: advanced preparation of inclusion bodies and design of refolding experiments.


Expression systems

  • Microbial

    • Bacterial : E.coli
    • Yeast : Pichia pastoris, Saccharomyces cerevisiae, Yarrowia lipolytica


  • Mammalian

    • CHO
    • HEK
    • Hybridoma



  • Microbial (E.coli, yeasts)
    • Erlenmeyer : up to 16L
    • Fermentor : up to 10L

  • Mammalian

    • Erlenmeyer : up to liters scale
    • Wave : up to 25L
    • Bioreactor :
      • 4*2L for development
      • up to 12.5L for production
    • Flask to cell factory for adherent cells