RapidVax®: A Customizable Approach to Countering Emerging Biological Threats

Vaccine development historically has been an imperfect art. Safety concerns and challenges with pathogen biodiversity and prolonged development cycles have raised questions over whether conventional and newer mRNA vaccines are suitable to combat emerging infectious diseases. RapidVax utilizes a common unprogrammed vaccine base designed to promote immunological memory and capable of being stockpiled and rapidly customized upon identification of a biological threat to harness shared development, clinical safety, and manufacturing synergies.

How it works

  • RapidVax couples our gp96 platform with the T-cell costimulatory molecule OX40L and a flexible antigen expression system to generate pathogen-specific vaccines.
  • Target pathogen antigens are identified, sequenced, and transfected into a common base cell expressing gp96-Ig and OX40L-Ig.
  • Pathogen antigens bound to gp96-Ig are released from the cell, stimulating the innate immune toll-like receptors 2 and 4 on Antigen Presenting Cells (APCs) to promote activation and uptake via CD91.
  • Processed antigens (peptides) are then presented by APCs to facilitate T cell activation.
  • OX40L-Ig released from the RapidVax base cell stimulates OX40 on activated T cells to promote the generation of memory T cells and the expansion of T follicular helper cells that can support B cell antibody production.

RapidVax by the numbers


External Collaborations


Preclinical Targets



Advantages of the RapidVax Platform

  • Unprogrammed RapidVax vaccines are designed to be manufactured in bulk, stockpiled, and rapidly customized to accelerate time to clinic by harnessing optimizations in preclinical development, safety, and manufacturing.
  • Customizable antigen delivery system: target sequences can be transfected into pre-manufactured RapidVax vaccine cells to generate a pathogen-specific immune response.
  • Multivalent potential designed to address pathogen heterogeneity.
  • Engineered for long-term protection via the stimulation of antibody production and generation of immunological memory.
  • A ‘Made in America’ development and manufacturing model to limit potential supply chain vulnerabilities
  • Favorable clinical trial safety profile previously observed for our gp96 platform.
  • Immunogenicity and prophylactic protection observed in response to gp96/OX40L based vaccines in preclinical models of infectious agents including malaria, HIV/SIV, Zika and SARS-CoV-2 virus.1-5

RapidVax Platform Development

  • Infectious Disease: RapidVax leverages our experience developing gp96-based vaccines and couples the immune-activating properties of gp96 and the T cell co-stimulator OX40L with a flexible antigen expression system to generate pathogen-specific vaccines. Platform development and preclinical evaluation of RapidVax as a medical countermeasure are currently underway.


1Strbo et al 2013 J Immunol 57:311 325

2Strbo et al 2016 J Immunol 196 (1 Supplement) 146.10

3Strbo et al 2013 J Immunol 190(6): 2495–2499

4Strbo et al 2018 J Immunol 200 (1 Supplement) 180.19

5Fisher et al 2021 Frontiers in Immunology, 11:602254