The Food and Drug Administration (FDA) has approved Inmazeb® (atoltivimab, maftivimab, and odesivimab-ebgn; Regeneron) for the treatment of infection caused by Zaire ebolavirus in adult and pediatric patients, including newborns of mothers who have tested positive for the infection.

Inmazeb consists of 3 recombinant human IgG1κ monoclonal antibodies that bind to different, non-overlapping epitopes on Zaire ebolavirus glycoprotein simultaneously, blocking attachment and entry of the virus. The triple-antibody cocktail utilizes the Company’s proprietary VelocImmune® platform to help neutralize the virus.  

The approval was based on data from the randomized, controlled phase 2/3 PALM trial that compared the efficacy and safety of Inmazeb to the control arm, in addition to optimized standard of care. The trial enrolled 681 patients of all ages who had Ebola during an outbreak in August 2018 in the Democratic Republic of the Congo. Patients were randomized to receive Inmazeb (50mg of each antibody per kg) intravenously as a single infusion (n=154) or an investigational control (n=168).

The primary efficacy end point was 28-day mortality. The primary analysis population included all patients who were randomized and concurrently eligible to receive either Inmazeb or the investigational control during the same time period of the trial.

Among patients treated with Inmazeb, results showed a 28-day mortality rate of 34% (n=52) compared with 51% (n=78) for the control arm (difference -17.2%; 95% CI, -28.4, -2.6; P =.0024). In August 2019, the PALM trial was stopped early due to preliminary data that showed a statistically significant reduction in mortality for Inmazeb compared with control. The most common adverse reactions observed in patients who received Inmazeb were pyrexia, chills, tachycardia, tachypnea, and vomiting.

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Inmazeb will be supplied as a preservative-free solution containing 241.7mg of atoltivimab, 241.7mg of maftivimab, and 241.7mg of odesivimab-ebgn per 14.5mL in single-dose vials.

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  2. Regeneron’s antibody cocktail regn-eb3 (Inmazeb®) is first FDA-approved treatment for Ebola (Zaire ebolavirus). [press release]. Tarrytown, NY: Regeneron Pharmaceuticals; October 14, 2020.
  3. Inmazeb [package insert]. Tarrytown, NY: Regeneron Pharmaceuticals; 2020.