In early 2018, Nigeria has witnessed an unprecedented LF outbreak, whereby the usual annual observed LF burden has been concentrated into one trimester. From 1st January to 29th April 2018, a total of 1878 suspected cases have been reported from 21 states. Of these, 420 were confirmed positive.
The endemicity of LASV in West-Africa and the occurrence of LF outbreaks have underscored the need to develop Lassa therapeutics. The WHO R&D Roadmap of LF notably identifies the following strategic goals:
- More fully evaluate ribavirin for treatment of Lassa fever and determine the appropriate role of ribavirin in clinical trials of new therapeutics.
- Develop, evaluate, and license new and improved affordable therapeutic agents for treatment of Lassa fever and prevention of Lassa fever-associated sequelae, as well as for PrEP/PEP to prevent LASV infection, for the multiple LASV lineages.
Based on those goals, WHO convened on April 2018 a group of about 30 experts in epidemiology, regulatory, preclinical and clinical trials, in a workshop on planning for Lassa therapeutics efficacy trials. The workshop aimed to define generic principles on how to best design, conduct and analyse therapeutics trials against LF, based on the available scientific evidence as well as on lessons learned from the public health response to LF outbreaks.
According to the R&D Blueprint processes, conclusions of the R&D Roadmap of LF and a WHO Lassa therapeutic Target Product Profile (DRAFT) were expected to help inform therapeutic evaluation decisions during the workshop. Participants reviewed available evidence on Lassa epidemiology and therapeutic candidates, identified and discussed methodological options to evaluate therapeutics, regardless of the product, and agreed on some preliminary recommendations. Of note, post-exposure prophylaxis was excluded from the scope of the workshop.
It was recognised both that the preliminary recommendations are likely to evolve as new evidence is generated and also, they must be tailored to the social and cultural context of affected communities.