Requiring More Data, FDA Sets Back COVID-19 Treatment Ensovibep

Ensovibep, the COVID-19 antiviral treatment developed by Novartis and Molecular Partners, is facing delays in its quest for emergency authorization after the FDA indicated more study data is required.

Novartis is reportedly reconsidering pushing for approval of their experimental COVID-19 treatment, ensovibep, after the US Food and Drug Administration (FDA) indicated needing more research.

Novartis originally filed for FDA approval of their antiviral candidate in early February 2022, following a mid-stage trial demonstrating a single injection of ensovibep significantly reduced COVID-19 hospitalization and death.

Novartis and Molecular Partners, a Swiss drug company that originally developed ensovibep, paid $22 million last year for the option to in-license the COVID-19 therapy.

Company executives are currently in conversation with the FDA to determine the kind of late-stage research required for ensovibep’s emergency authorization.

Ensovibep is a Designated Ankyrin Repeat Protein (DARPin) that hinders the SARS-CoV-2 virus from entering cells. With protein scaffolds much smaller than monoclonal antibodies, ensovibep binds to 3 parts of the virus’s receptor-binding domain.

Novartis and Molecular Partners joined forces in October 2020, back when there were few to no COVID-19 prevention or treatment options. Today, vaccines are widely available and there are many promising treatments.

Ensovibep will certainly face delays in FDA approval, and may even opt to abandon the project. Novartis is deciding whether to continue pushing for FDA authorization “in light of waning rates of COVID around the world,” said CEO Vas Narasimhan.

Ensovibep previously neglected to clear the efficacy requirements in the National Institutes of Health (NIH) ACTIV-3 trial. The therapy failed a planned futility analysis, leading the NIH to stop enrollment in the ACTIV-3 sub-study.

Novartis emphasized that the prospect of a single injection for COVID-19 treatment is still exciting to the FDA. Ensovibep has maintained its efficacy against all major variants of concern, including Omicron. “Certainly, we believe in the profile of the molecule,” Narasimhan said.