On September 29th, Regeneron published the first data and findings from a descriptive analysis of a seamless Phase 1/2/3 trial of its investigational antibody cocktail REGN-COV2 showing it reduced viral load and the time to alleviate symptoms in non-hospitalized patients with COVID-19. REGN-COV2 also showed positive trends in reducing medical visits. The ongoing, randomized, double-blind trial measures the effect of adding REGN-COV2 to usual standard-of-care, compared to adding placebo to standard-of-care.
Regeneron’s data is bit hard to understand for non-science readers – more about the viral load counts – but this is the most important part:
Patients with increasingly higher baseline viral levels had correspondingly greater reductions in viral load at Day 7 with REGN-COV2 treatment. The mean log10 copies/mL reduction in viral load compared to placebo were as follows:
Viral load higher than 105 copies/mL: high dose (-0.93); low dose (-0.86) (p=0.03 for both); approximately 50-60% reduction compared to placebo
Viral load higher than 106 copies/mL: high dose (-1.55); low dose (-1.65) (p<0.002 for both); approximately 95% reduction compared to placebo
Viral load higher than 107 copies/mL: high dose (-1.79); low dose (-2.00) (p<0.0015 for both); approximately 99% reduction compared to placebo.
The higher the viral load – the worse the infection – the better it worked. That’s what we are looking to apply to the immunoprevention use case: the antibodies are very directly neutralizing the virus and preventing reproduction.
It was also encouraging that the greatest improvements were seen in patients who had not mounted their own effective immune response prior to treatment. This indicates that antibodies may also be effective and useful for patient populations – the elderly and those with preexisting conditions – that may get as much protection as desired from vaccines.