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With FDA nod, Ridgeback’s Ebanga joins Regeneron’s Inmazeb in the Ebola-fighting arsenal

Nearly seven years after the largest Ebola epidemic broke out in West Africa, two drugs against the deadly virus are now available.

The FDA has approved Ridgeback Biotherapeutics’ Ebanga, or ansuvimab, to treat Zaire ebolavirus infection. The drug was originally developed by the National Institutes of Health and licensed to the Miami biotech.

Monday’s approval marks the second for an Ebola drug after Regeneron’s Inmazeb, a cocktail of three monoclonal antibodies, claimed the first title in October.

Both Ebanga and Inmazeb were tested in the PALM study conducted during the 2018-19 outbreak in Congo. The trial pitted the drugs against Mapp Biopharmaceutical’s ZMapp or Gilead’s remdesivir—which recently became the first FDA-approved COVID-19 therapy. The two drugs in the control arm have never been approved for Ebola but were at the time considered the standard of care.

The study showed patients on Ebanga were more likely to survive than those in the control arm. Of the 174 patients who received Ebanga, 35.1% died after 28 days, compared with 49.4% of the 168 control patients.

Approvals for the Ebola treatment came months later than the green light for the first Ebola vaccine, Merck’s Ervebo. Neither Ebanga nor Inmazeb can be concurrently administered with Ervebo because the two antibodies could kill off the live virus antigen contained in the vaccine and therefore reduce its efficacy.

Sporadic outbreaks have been identified in Congo, with the most recent one beginning in June and declared over in mid-November after claiming the lives of 55 people.

Both Ridgeback and Regeneron have recently pivoted their antiviral know-how to COVID-19. Regeneron has again pursued the antibody cocktail path, as its REGN-COV2, a combination of casirivimab and imdevimab, won FDA an emergency use authorization for outpatient treatment. 

In June, Ridgeback ushered its COVID-19 candidate molnupiravir (EIDD-2801) into two separate phase 2 trials in outpatients and hospitalized patients. The company has licensed the drug’s exclusive global rights to Merck & Co.