# Development of an adaptable RNA vaccine against enterovirus D68 infection for the prevention of acute flaccid myelitis

> **NIH NIH R43** · HDT BIO CORPORATION · 2021 · $299,976

## Abstract

Project summary:
First identified in California in 2012, acute flaccid myelitis in children, associated with enterovirus D68 (EV-D68)
infection, has been increasing in incidence with outbreaks detected every 2 years. Enteroviruses are well-known
causes of central nervous system pathologies, ranging from aseptic meningitis to sometimes fatal brainstem
encephalitis and myelitis, which can lead to permanent debilitating paralysis. Additionally, EV-D68 infects the
respiratory tract, causing severe respiratory disease and facilitating person-to-person transmission via
respiratory droplets. Despite EV-D68’s emergence as a major cause of severe respiratory and neurological
disease, there are no vaccines or therapeutics available to combat and control the spread of this pathogen.
HDT Bio has developed a self-amplifying replicon RNA (repRNA) vaccine platform delivered by a Lipid InOrganic
Nanoparticle (LION) scheduled to enter phase I clinical trials in the first quarter of 2021 as a vaccine against
COVID-19. These activities will enable rapid translation of other vaccine candidates, utilizing the same platform,
into the clinic. Additionally, HDT has an ongoing program to develop broad-spectrum anti-EV-D68 antibody
therapeutics, in which we have identified promising RNA-based vaccines that encode the necessary genes for
production of divergent EV-D68 virus like particles (VLPs) in vivo upon intramuscular administration. Our
preliminary data establishes that 1) we can launch VLPs of non-enveloped viruses from our repRNA platform, 2)
we can rapidly adapt this approach for genotypic and/or antigenic variants of EV-D68, and 3) these antigens are
very immunogenic in small and large animals, generating robust neutralizing antibody responses after a single
dose. In this application, we propose to screen six vaccine candidates, which are currently being evaluated as a
mixture in alpacas for antibody discovery efforts, to identify a single candidate that induces the best cross-
neutralizing antibody responses. We will then characterize safety, immunogenicity and efficacy in neurological-
and respiratory-disease mouse models of EV-D68 infection. Finally, we will evaluate safety and immunogenicity
in pregnant mouse models and efficacy in birthed pups while characterizing maternal antibody transfer.

## Key facts

- **NIH application ID:** 10325201
- **Project number:** 1R43AI165100-01
- **Recipient organization:** HDT BIO CORPORATION
- **Principal Investigator:** Jesse Hong-Sae Erasmus
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $299,976
- **Award type:** 1
- **Project period:** 2021-09-03 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10325201

## Citation

> US National Institutes of Health, RePORTER application 10325201, Development of an adaptable RNA vaccine against enterovirus D68 infection for the prevention of acute flaccid myelitis (1R43AI165100-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10325201. Licensed CC0.

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