Lassa Fever Vaccine Efficacy And Prevention for West Africa (LEAP4WA)

Lassa fever (LF), a severe viral disease endemic in West African countries including Guinea, Liberia, Nigeria, Sierra Leone with approximately 300,000 LF cases and 5,000-10,000 deaths annually. However, these numbers are likely severely underestimated because of limited disease surveillance. Unprecedented recent large outbreaks in Nigeria further highlight the urgency to develop Lassa virus (LASV) vaccines. Currently, a partner consortium, led by IAVI, is advancing a Lassa vaccine candidate (rVSVdG-LASV-GPC) based on the recombinant vesicular stomatitis virus (rVSV) platform technology through Coalition for Epidemic Preparedness Innovations (CEPI) support. This rVSV-based LASV vaccine has a strong probability of technical feasibility, safety and success in preventing LF. The vaccine candidate demonstrated 100% efficacy in a non-human primate challenge study. Furthermore, it uses the same technology as Merck’s ERVEBO® vaccine that has been shown to be safe and efficacious in preventing Ebola virus disease and was licensed by the European Medicines Agency and Food and Drug Administration and prequalified by the WHO. This vaccine has been administered to over 300,000 people, induces protective immunity rapidly with a single dose and can be readily manufactured at large scale. The Lassa Fever Vaccine Efficacy and Prevention for West Africa (LEAP4WA) project, in accordance with the EDCTP2 research agenda goals, will accelerate further development of this rVSVdG-LASV-GPC vaccine through the conduct of an innovative safety and efficacy phase 2b trial that will enroll adults and children from communities in Nigeria, Sierra Leone, and Liberia. This endpoint-driven trial design includes an adaptive element that allows trial size to increase if necessary, to accrue sufficient cases for a definitive result, following an interim look by an independent Data Monitoring Committee. This project will bring together 9 collaborators from Africa, Europe and the United States to facilitate the preparation of investigational sites in outbreak countries, including Nigeria to allow assessment of vaccine cross-protection. LEAP4WA will also strengthen clinical research capacity in West Africa by building partnerships in countries most impacted by LF and across networks of excellence for LF research and vaccine development. The partner consortium will utilize their collective experience to enhance capacity of a network of clinical research centres capable of conducting EID vaccine trials. This effort is expected to significantly advance the development of a LF vaccine portfolio and provide important proof of concept data that will contribute directly to product licensure and ultimately access to much needed LASV vaccines.