Vaxiclase is our proprietary reengineering of the native adenylate cyclase (CyaA).
It can be used in two different ways, as an antigen delivery vector or as an active ingredient (pertussis antigen).

  • When used as an antigen delivery vector, Vaxiclase retains all the functionalities of the CyaA vector. A specific deletion in its N-terminal domain enables the translocation of larger or multiple exogenous antigens. This ability makes possible the development of multivalent immunotherapies against various diseases. GTL002 was developed using Vaxiclase.
  • When used as the antigen of pertussis (whooping cough), without other exogenous antigens. Vaxiclase both induces anti-CyaA antibodies against pertussis and increases the production of antibodies against other antigens, such as when used for DTaP vaccines. It also induces a “memory” immune response for a long-lasting efficacy.

This latest application is the one that was licensed to Serum Institute of India Ltd. (SIIL) in February 2015. When used as an antigen, Vaxiclase is in itself a product candidate called GTL003.

Improving pertussis vaccines

Former cellular Pertussis vaccines were efficacious but not well tolerated. In turn, current acellular Pertussis vaccines (aP) are very well tolerated but with an insufficient duration of efficacy. As a result, there is a marked global resurgence of pertussis cases worldwide observed by WHO1.

GTL003 (Vaxiclase as a pertussis antigen) could improve the duration of protection of aP vaccines but with a good tolerability2.

The estimated global market for combination vaccines DTaP and Tdap containing aP exceeds $2 billion per year.

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The agreement with Serum Institute of India

In February 2015, we licensed GTL003, our Vaxiclase technology as an antigen, to Serum Institute of India Pvt. Ltd. (Serum Institute), for use in the development of acellular multivalent combination vaccines including pertussis antigens.

Serum Institute ( is a private company valued at over $12 billion and the world's largest producer of the Measles and DTP group of vaccines. Two of every three children immunized globally are vaccinated with a product manufactured by Serum Institute.

The license granted by Genticel to SIIL provides GTL003 for inclusion in multivalent vaccines that also protect against Bordetella pertussis, the causative agent of whooping cough. The license covers all countries of the world except major pharmaceutical markets, in particular the USA, Canada, New Zealand, Australia, Japan, Israel, Turkey and greater Europe.

In exchange for the access and use of GTL003 in the licensed indication, Genticel is eligible for up to $57 million in upfront, development & sales milestone payments from SIIL, as well as single digit royalties on net sales.

In November 2016, the last preclinical milestone in the partnership was reached, opening the path to formal preclinical testing prior to clinical development and subsequent commercialization.


  1. WHO: Weekly epidemiological record, 85, 2010 (; Klein et al., New England Journal of Medicine, 367(11), 2012;

  2. Koepke, Journal of Infectious Disease, 210, 2014; [2] Cheung et al., Infection and Immunity, 74(12), 2006.

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