6 July 2020 - - US-based biotechnology company Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) has initiated late-stage clinical trials evaluating REGN-COV2, Regeneron's investigational double antibody cocktail for the treatment and prevention of COVID-19, the company said.

A Phase 3 trial will evaluate REGN-COV2's ability to prevent infection among uninfected people who have had close exposure to a COVID-19 patient (such as the patient's housemate), and is being run jointly with the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. 

REGN-COV2 has also moved into the Phase 2/3 portion of two adaptive Phase 1/2/3 trials testing the cocktail's ability to treat hospitalised and non-hospitalized patients with COVID-19.

This clinical progress follows a positive review from the Independent Data Monitoring Committee of REGN-COV2 Phase 1 safety results in an initial cohort of 30 hospitalized and non-hospitalized patients with COVID-19.

The Phase 3 prevention trial is being conducted at approximately 100 sites and is expected to enroll 2,000 patients in the US; the trial will assess SARS-CoV-2 infection status.

The two Phase 2/3 treatment trials in hospitalized (estimated enrollment =1,850) and non-hospitalized (estimated enrollment =1,050) patients are planned to be conducted at approximately 150 sites in the US, Brazil, Mexico and Chile, and will evaluate virologic and clinical endpoints, with preliminary data expected later this summer.

All trials are adaptively-designed, and the ultimate numbers of patients enrolled will depend on trial progress and insights from Phase 2 studies.

Regeneron scientists evaluated thousands of fully-human antibodies produced by the company's proprietary VelocImmune mice, which have been genetically-modified to have a human immune system, as well as antibodies isolated from humans who have recovered from COVID-19.

They selected the two most potent, non-competing and virus-neutralizing antibodies to create REGN-COV2 and have scaled up this dual-antibody cocktail for clinical use with the company's in-house VelociMab and manufacturing capabilities.

REGN-COV2's two antibodies bind non-competitively to the critical receptor binding domain of the virus's spike protein, which diminishes the ability of mutant viruses to escape treatment and protects against spike variants that have arisen in the human population, as detailed in recent Science publications.

More recent research also demonstrates coverage against the now prevalent D614G variant.

Regeneron used the same 'rapid response' capabilities and cocktail approach to develop REGN-EB3, a novel triple antibody treatment for Ebola that is now under regulatory review by the FDA.

REGN-COV2's development and manufacturing has been funded in part with federal funds from the BARDA under OT number: HHSO100201700020C.