Novartis and Molecular Partners have announced positive results from Part A of the EMPATHY clinical trial of an antiviral, ensovibep, to treat Covid-19.

A Designed Ankyrin Repeat Proteins (DARPin) treatment candidate, ensovibep can precisely inactivate the SARS-CoV-2 virus. 

Part A of the trial, which assessed single intravenous doses of the antiviral versus placebo, met the primary goal of offering a statistically significant decline in viral load over eight days.

Carried out by Novartis and sponsored by Molecular Partners, the randomised, placebo-controlled, double-blind, international trial enrolled adult subjects with Covid-19 in an ambulatory (non-hospitalised) setting.

Part A of the Phase II trial recruited 407 subjects in the US, Netherlands, India, South Africa, and Hungary to identify the optimal dose of ensovibep.

It evaluated three varying doses of the antiviral: 75mg, 225mg and 600mg.

According to trial results, clinically meaningful benefit over placebo was reported in the two secondary endpoints: composite endpoint of hospital admission and/or Emergency Room (ER) visits or morality; and time to sustained clinical recovery. 

An overall decline of 78% in the risk of hospitalisation and/or ER visits or death was observed across all ensovibep groups versus placebo. 

Furthermore, no cases of death were noted in the subjects who received the antiviral treatment with all doses found to be well-tolerated without any unexpected safety issues.

The companies plan to use the 75mg dose of ensovibep for further development. 

In addition, Novartis announced plans to exercise its option for the in-licensing of ensovibep from Molecular Partners for $163m (CHF150m).

Novartis will handle the therapy’s development, production and marketing activities. 

In the initial stage, the company will seek emergency use authorisation (EUA) from the US Food and Drug Administration for ensovibep.

Novartis CEO Vas Narasimhan said: “We are pleased that the results from the EMPATHY trial demonstrate the positive therapeutic effect of ensovibep, with the potential to be an important new treatment option to combat the rapidly evolving SARS-CoV-2 pandemic. 

“As Covid-19 continues to burden healthcare systems across the globe, a range of treatments will be needed, and Novartis is proud to continue our collaboration with Molecular Partners on this unique treatment for Covid-19 and contribute ensovibep to this suite of options.” 

Ensovibep showed great neutralisation activity against variants of SARS-CoV-2, including Delta and Omicron, in in vitro testing.

In May 2021, the companies started the Phase II/III EMPATHY trial of ensovibep (MP0420) for Covid-19.