Regeneron Pharmaceuticals (NASDAQ:REGN) announces preliminary data from a seamless Phase 1/2/3 clinical trial evaluating its antibody cocktail, REGN-COV2, plus standard-of-care treatment in non-hospitalized COVID-19 patients.
Results are from the first 275 participants with confirmed COVID-19 infection who were randomized 1:1:1 to receive either a one-time infusion of 8 gm of REGN-COV2 (high dose), 2.4 gm (low dose) or placebo. Patients were classified as seropositive (measurable SARS-CoV-2 antibodies) (45%), seronegative (no measurable antibodies) (41%) or other (unclear or unknown serology status) (14%).
The serologic status was highly correlated with baseline viral load. Seronegative patients had much higher viral loads than seropositives and cleared the virus more slowly in the absence of treatment. In the control arm, median time to alleviation of symptoms in the seropositive group was seven days, compared to 13 days in the seronegative group.
Seronegative patients receiving low-dose REGN-COV2 showed a mean time-weighted-average change from baseline in nasopharyngeal viral load of 0.51 log10 copies/mL greater than placebo, while the relative benefit was 0.60 log 10 copies/mL in the high dose arm.
In the overall population, the relative viral load reductions for high- and low-dose REGN-COV2 were 0.51 log10 copies/mL and 0.23 log 10 copies/mL.
Patients with increasingly higher viral loads have correspondingly greater viral load reductions at day 7. The approximate reductions in patients with viral loads higher than 105 copies/mL, 106 copies/mL and 107 copies/mL were ~50-60%, ~95% and ~99%, respectively.
Predictably, seronegative patients, or those with higher baseline viral levels, experienced greater benefits from REGN-COV2. In seronegatives, median time to symptom alleviation was six days in the low-dose arm, eight days in the high-dose arm and 13 days in the control arm.
Seronegatives were at higher risk of medically attended visits. 4.9% in the high-dose required additional medical visits, compared to 7.7% in the low-dose arm and 15.2% in the placebo arm.
On the safety front, both doses of REGN-COV2 were well-tolerated. Infusion reactions were observed in four participants: two in the control arm and two in the treatment arms. Three experienced serious adverse events: two in the control arm and one in the low-dose arm.
REGN-COV2 consists of two monoclonal antibodies – REGN10933 and REGN10987 – designed to block the infectivity of SARS-CoV-2.
Management is currently hosting a conference call discussing the results.
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