The FDA has accepted Regeneron’s filing for approval of the Ebola drug REGN-EB3 for priority review. REGN-EB3, which comes from the same platform as Regeneron’s COVID-19 antibodies, arrives at the FDA after outperforming ZMapp in a clinical trial.
In securing a priority review at the FDA, Regeneron has positioned itself to learn whether it has won approval for the drug by Oct. 25. The treatment, a cocktail of three antibodies against Ebola, has orphan drug status and breakthrough therapy designation.
FDA approval would add a new and, based on clinical trial data, more effective medicine to the armory available to physicians treating Ebola patients. The recent flare-up in Ebola cases in Congo, and risk of further outbreaks, show the importance of having such a tool. Yet, the scale of the COVID-19 crisis means Regeneron’s work on Ebola is also being seen through the prism of what it means for efforts to get a handle on the pandemic.
Working with the Biomedical Advanced Research and Development Authority, Regeneron used its VelocImmune mouse model and associated technologies to generate fully human antibodies against the Ebola virus, enabling it to identify candidates without using blood from people who had survived infection with the pathogen. REGN-EB3 went on to prove itself in a clinical trial that compared it and two other drugs to Mapp Biopharmaceutical’s ZMapp.
REGN-EB3 was one of two drugs to outperform ZMapp in the Ebola clinical trial. The drug that failed to move the needle was remdesivir, the Gilead antiviral that is now among the most advanced assets in development against COVID-19.
Regeneron’s COVID-19 program is less advanced, with clinical trials slated to start in June, but hopes are higher for its antibodies than they are for remdesivir. Those hopes are underpinned by a body of experience of using antibodies to neutralize other viruses, including Ebola.
In the Ebola trial, 33.5% of patients who received REGN-EB3 were dead 28 days later, as compared to a 51.3% mortality rate among their peers in the ZMapp control cohort. The difference resulted in the trial hitting its primary endpoint with a p value of 0.002. Among patients who received REGN-EB3 early in the course of their disease, the death rate was 10%.
COVID-19 is caused by a different virus, namely SARS-CoV-2, but the processes Regeneron is using to discover, develop and manufacture antibodies for use in the ongoing pandemic are the same.