The May 2018 Ebola outbreak in the Democratic Republic of the Congo (DRC) prompted the World Health Organization (WHO) to convene committee panels of relevant experts for deliberations on the merits of investigational therapeutics, with a particular focus on clinical trial design. GlobalData foresees an increase in R&D investment for Ebola diagnostics, therapeutics, and vaccines, now that the WHO is developing relevant R&D frameworks to guide academia, government, and industry in creating products to combat this deadly and unpredictable disease.
At least two WHO report notes were published from the Ebola-related deliberations. The first WHO report provides an explanation on the application of the Monitored Emergency Use of Unregistered Interventions (MEURI) framework regarding Ebola. A series of investigational Ebola therapeutics were considered for deployment during the current Ebola outbreak based on available efficacy data. MEURI application occurs when clinical trial data for an intervention is inadequate to meet traditional intervention evaluation standards. The MEURI expert panel found ZMapp (Mapp Biopharmaceutical) along with REGN3470-3471-3479 (Regeneron Pharmaceuticals) as among the more promising therapeutics, given their limited clinical data. Remdesivir (Gilead) and mAb114 (US NIH/DRC) also were noted as promising therapies. Already, the US Biomedical Advanced Research and Development Authority (BARDA) has invested at least $80M for ZMApp’s and Regeneron’s Ebola therapies development and purchase.
Given the high virulence of Ebola, randomized control trials (RCTs) in humans that include one or more placebo arms for efficacy analysis of the investigational therapeutic have been eschewed for ethical reasons. Instead, clinical trial efficacy data from animal trials that include pathogen challenge data are relied upon as replacement for placebo efficacy comparison involving humans. The FDA’s Animal Rule for product licensure was established for such circumstances of difficult-to-administer clinical trials for assessing therapeutic efficacy in humans. Nonetheless, the safety of the investigational therapeutic in humans must be assessed before licensure.
The second WHO report discusses the expert panel’s agreement on acceptable clinical trial designs, without placebo, for assessing the efficacy of investigational Ebola therapeutics for humans. A three-arm, open-label, randomized trial, which doesn’t include a placebo arm, was determined as the best approach for determining therapeutic efficacy and safety given the circumstances. In a 1:1:1 ratio, therapy treatments are randomized among participants with efficacy and safety data obtained by comparing the clinical endpoints data of combined therapy groups with each individual therapy. This is the recommended clinical trial design going forward for further Ebola therapeutics R&D. While this clinical trial design is not as robust as an RCT that includes a placebo arm, it is an acceptable alternative for obtaining reliable therapeutic clinical trial data while avoiding ethical concerns regarding Ebola.
The establishment of a WHO clinical trial design framework for Ebola R&D pipeline products facilitates the process for their regulatory approval, lowering the regulatory obstacles to preventing and treating this terrifying disease.