Our production process: high quality first

As a CDMO expert in lentiviral vector design and manufacturing since 2005, we produce very pure and highly concentrated integrative lentiviral (iLVs) and non-integrative LentiFlash® particles (biological RNA delivery technology). We will assist you from discovery to clinical studies and adapt the production scale and the vector quality according to your needs.

Manufacturing dyptique

High quality lentiviral vector production

With over 16 years of know-how in lentiviral technology and a robust and proprietary bioproduction process, Flash Therapeutics has produced more than 8000 lentiviral vector batches for scientists and clinicians all over the world.

Flash Therapeutics can support you for the design of your project, then we take care of all steps to provide integrative lentiviral particules or LentiFlash® particles for RNA transfer.

Quality of lentiviral vectors

Flash Therapeutics offers small, medium and large-scale productions of high-quality vectors from R&D grade to GMP grade.

2G or 3G lentiviral vector depending on your needs

Three plasmids for second generation (2G) or four plasmids for third generation (3G) will be used to produce lentiviral particles. 
Helper Plasmids have been optimized (removal of unnecessary viral components, codon optimization…).

If needed, we can support you with the optimization of your expression construct as well.

2G lentiviral vectors:

A first plasmid provides a nucleic acid encoding viral Gag, Pol and Rev genes lacking vif, vpr, vpu, and nef genes.

A second plasmid provides a nucleic acid encoding the vesicular stomatitis virus envelope glycoprotein (VSV-G) in order to pseudotype the particules.

A third self-inactivating transfer plasmid (deletion in the 3' LTR) contains the transgene-s of interest under the control of the chosen promoter.

3G lentiviral vectors:

Transfer and VSV-G envelope plasmids remain the same as for 2G production.

Then we utilizes split-genes to provide the viral packaging elements in order to reduce the risk of RCL (Replication Competent lentivirus) : A first plasmid provides a nucleic acid encoding viral Gag, Pol and a second plasmid carries the Rev sequence (used only for integrative vector production). We further reduced the risk of RCL by removing the Tat gene from the Rev plasmid.

These improvements significantly increase the safety profile of our lentiviral vectors, which can be used in category II laboratories in most EU and other countries. We can produce 3G vectors even at a discovery level project, to facilitate future clinical translation.

Packaging Plasmids of lentiviral vectors

A robust lentiviral vectors production & purification

Even if manufacturing processes differ for the different vectors used in gene therapy, a common requirement is an efficient purification of the product to remove any contaminating viral components that can have a detrimental effect on target cells. 

Investment in manufacturing started early in our development, as we consider that providing high quality products is a success factor for the development of cell and gene therapy but also at the discovery level, to ensure robustness of data obtained and their possible clinical translation.

Our lentiviral manufacturing platform provides the highest purity on the market.

A premium production process for premium vector quality 

  • Adherent cells (HEK293T)
  • Serum and antibiotic free media, to limit contaminants
  • CS or HS or Bioreactor, according to the final volume needed
  • Several successive purification steps
  • Single use technology


Steps of purification process

Flash Therapeutics production process allows removal of most of proteins and DNA impurities. This high purity level avoids phenotype changes or unwanted cellular responses following transduction. 

Flash Therapeutics also developed a reliable and discriminating titration method based on the actual content of effective particles, quantified by qPCR in integrated Virus Genome units (IG). This ensures that we do not include in our titles the total number of particles including damaged or empty particles and guarantees robust and reproducible performances of vector batches.
We can also give a PP/IG ratio (on demand) which provides a good measure of the quality of the vector produced. This is part of our requirements for transparency and quality.

GMP manufacturing and purification of selected and optimized candidates.

As a CDMO, Flash Therapeutics has its cGMP compliant lentiviral vectors production platform for clinical applications, based on its know how on high quality vectors production.

GMP grade lentiviral vector manufacturing

GMP-grade lentiviral vectors manufacturing for lentivectors used as starting material. An additional chromatography step is included for lentivectors used as drug product.

Different products for each stage of your project

Flash Therapeutics offers two qualities of vector depending on your applications: 

  • Start quality (>107 IG/ml) for Research-grade vectors 
    • Very high level of transduction on permissive and “hard-to-transfect” immortalized cell lines

Start is dedicated to screen and select the best vector candidates. 

  • Premium quality (>109 IG/ml) for Research-grade to GMP-grade vectors 
    • Very high level of transduction on primary & stem cells 
    • No cell damage thanks to the low impurity content 
    • Safe and clinically  suitable delivery without inducing toxicity or immunogenicity 
    • In vivo genetic transfer

Premium is dedicated to in vitro or ex vivo approaches, in vivo gene therapy, transgenesis or direct tissue injection experiments.

Bacth type for quality lentiviral vectors

Start and Premium quality lentiviral vector specifications