# Recombinant Outer Membrane Vesicles as a Novel Adjuvant for a Malaria Vaccine

> **NIH NIH R44** · VERSATOPE THERAPEUTICS, INC. · 2024 · $999,762

## Abstract

Abstract
While vaccines are an integral component of disease management, vaccine technologies remain inadequate for
addressing malaria. Malaria caused by Plasmodium falciparum remains a global public health concern, with
more than 229 million cases and 409,000 malaria-related deaths annually. The spread of drug-resistant parasites
and insecticide-resistant mosquitoes has exacerbated the problem of controlling malaria in many developing
countries in recent years. Current control measures such as bed nets, diagnostics, and drug treatment are
helpful, however, together with more effective vaccines that reduce infection and transmission, cases of
severe malaria may be eliminated. While an RTS,S virus-like particle vaccine targeting the sporozoite stage
of P. falciparum is available, it remains only 30% protective in children that receive the vaccine, leaving children
highly vulnerable. Versatope aims to address the unmet need for an effective malaria vaccine by
leveraging their powerful, flexible, and thermostable vaccine adjuvant platform. The power of the
technology platform is based on molecular engineering of recombinant outer membrane vesicles (rOMVs)
derived from a probiotic E. coli Nissle 1917 strain (BSL-1) engineered with a lipopolysaccharide (LPS) and
reduced endotoxicity. The resulting rOMVs are nano-sized particles that not only display foreign antigens of
interest but also serve as potent adjuvants for long-term immunological memory and the induction of neutralizing
and effector antibodies that protect against lethal pathogen challenge. rOMVs are stable under refrigerated
conditions and can also be lyophilized and formulated for increased stability at room temperature, facilitating
worldwide deployment. Using this platform, Versatope aims to deliver a malaria vaccine that acts as both a pre-
erythrocytic and transmission blocking vaccine, protecting against both infection and transmission. The
anticipated result of this Direct to Phase II proposal is selection and advancement of a malaria vaccine candidate
that prevents liver-stage infection and reduces mosquito-borne-transmission. The success of Versatope’s
malaria vaccine would represent a breakthrough in malaria reduction worldwide as an improved pre-erythrocytic
vaccine(s) with substantially improved properties over the pre-erythrocytic RTS,S vaccine currently in use.
Specifically, Versatope’s malaria vaccine would feature improved efficacy, longevity of immunity, reduced
number of vaccinations, thermostability, and a lower cost of goods. The new pre-erythrocytic rOMV vaccine will
target 70% efficacy in preventing new infections in infants and children. Together with a 70% reduction in
infections provided by bed nets, this could reduce the R by a factor 10. The combined reduction in
transmission of malaria provided by the pre-erythrocytic vaccine and current control measures (bed nets,
access to health care, early diagnosis, and chemotherapeutic treatment) may not only allow global h...

## Key facts

- **NIH application ID:** 10821792
- **Project number:** 1R44AI181242-01
- **Recipient organization:** VERSATOPE THERAPEUTICS, INC.
- **Principal Investigator:** Christopher Locher
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $999,762
- **Award type:** 1
- **Project period:** 2023-12-08 → 2026-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10821792

## Citation

> US National Institutes of Health, RePORTER application 10821792, Recombinant Outer Membrane Vesicles as a Novel Adjuvant for a Malaria Vaccine (1R44AI181242-01). Retrieved via AI Analytics 2026-05-29 from https://api.ai-analytics.org/grant/nih/10821792. Licensed CC0.

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