Our focus is developing high impact vaccines
against infectious diseases to improve human

Our technology allows us to readily manufacture VLPs displaying complex antigens to target a whole class of vaccine targets, such as RSV and SARS-CoV-2, with significant unmet medical needs

Virus-like Particles (VLPs)

VLPs enable high-density, multivalent display of antigens in a manner that closely resembles viruses. This induces stronger and more durable immunological responses compared to traditional soluble antigens. In addition, VLPs contain no genetic material, so they are non-infectious and can provide a safer alternative to live-attenuated or inactivated vaccines.

Icosavax was founded on breakthrough technology, developed at the Institute for Protein Design (IPD) at the University of Washington, that solves the problem of constructing and manufacturing VLPs displaying complex antigens. The technology generates computationally designed proteins that separate the folding of individual protein subunits from the assembly of the final macromolecular structure. The individual proteins are expressed and purified using traditional recombinant technologies and then self-assemble into VLPs when mixed together.

Naturally occurring VLPs have delivered effective licensed vaccines, including against human papillomavirus (HPV) and Hepatitis B. However, VLPs have been difficult to use for the display of complex heterologous antigens, like in the case of RSV.



Critical publications of Icosavax licensed VLP technology

Arunachalam, PS, et al. Adjuvanting a subunit COVID-19 vaccine to induce protective immunity. Nature (2021), 253–258.

Boyoglu-Barnum, et al. Quadrivalent Influenza Nanoparticle Vaccines Induce Broad Protection. Nature (2021), 623-628.

Walls AC, et al. Elicitation of potent neutralizing antibody responses by designed protein nanoparticle vaccines for SARS-CoV-2​. Cell (2020), 1367-1382.

Rappuoli R. and D. Serruto. Preview: Self-Assembling Nanoparticles Usher in a New Era of Vaccine Design. Cell (2019), 1245-1247.

Marcandalli J, et al. Induction of Potent Neutralizing Antibody Responses by a Designed Protein Nanoparticle Vaccine for Respiratory Syncytial Virus. Cell (pdf) (2019), 1420-1431.

Background third party publications on diseases and antigens relevant to Icosavax vaccine candidates

Hsieh CL, et al. Structure-based design of prefusion-stabilized human metapneumovirus fusion proteins. Nature Communications (2022).

Ruckward T, et al. Safety, tolerability, and immunogenicity of the respiratory syncytial virus prefusion F subunit vaccine DS-Cav1: a phase 1, randomised, open-label, dose-escalation clinical trial. The Lancet Respiratory Medicine (2021).

Crank MC, et al. A proof of concept for structure-based vaccine design targeting RSV in humans. Science (2019), 505-509.

Jain S. Epidemiology of Viral Pneumonia. Clinics in Chest Medicine (2017), 1-9.

Widmer K, et al. Rates of Hospitalization for Respiratory Syncytial Virus, Human Metapneumovirus, and Influenza Virus in Older Adults. Journal of Infectious Diseases (2012), 56-62.

Falsey A, et al. Humoral Immunity to Human Metapneumovirus Infection in Adults. Vaccine (2010), 1477-1480.

Falsey A, et al. Comparison of the Safety and Immunogenicity of 2 Respiratory Syncytial Virus (RSV) Vaccines–Nonadjuvanted Vaccine or Vaccine Adjuvanted with Alum–Given Concomitantly with Influenza Vaccine to High-risk Elderly Individuals. Journal of Infectious Diseases. (2008), 1317-1326.

Background third party publications demonstrating potential magnitude, duration, and breadth of response with VLP vaccines

Schiller J, and Lowy D. Explanations for the High Potency of HPV Prophylactic Vaccines. Vaccine (2018), 4768-4773.

Wheeler CM, et al. Cross-protective Efficacy of HPV-16/18 ASO4-adjuvanted Vaccine Against Cervical Infection and Precancer Caused by Non-vaccine Oncogenic HPV Types: 4-year end-of-study Analysis of the Randomised, Double-blind PATRICIA Trial. Lancet Oncology (2012), 100-110.