Promising results from Phase II REGEN-COV trials

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease (COVID-19) in 2019, has infected almost every country in the world, affecting more than 5 million people. I’m dead. Due to the rapid infection rate of SARS-CoV-2, many countries have enacted limited and costly social distance measures such as mandatory face masks, closure of public spaces, and even blockage / house-at-home orders. bottom.

While some developed countries have launched mass vaccination campaigns that allow most of these restrictions to be lifted, many developing countries have extensive cold chain logistics needed for proper vaccine storage. Or cannot provide resources. In addition, the development of a Variant of Concern (VOC) of SARS-CoV-2 continues, many showing increased infectivity and infectivity, and the ability to avoid both vaccine-induced immunity and innate immunity. increase.

study: Phase 2 dose-ranging study on the virological efficacy and safety of the combination therapy of COVID-19 antibody Casilibimab and Imdevimab in outpatients.. Image Credits: SmartPhotoLab / Shutterstock.com

About research

The need for COVID-19 treatment remains high, so researchers at Regeneron Pharmaceuticals are testing promising new drugs. REGEN-COV treatment is based on two antibodies, including Casilibimab and Imdevimab, given in a single intravenous (IV) or subcutaneous (SC) 1: 1 ratio.The first results of their Phase II study are presented in a recent study published on a preprint server. medRxiv*.

The researchers used a randomized, double-blind study in which the parallel control group was given placebo. In this study, we looked at different doses.

Nasopharyngeal (NP) swabs and blood cells were collected every other day for the first week and monthly for the next four months. All study participants were 18 years of age or older and had a positive SARS-CoV-2 test within 72 hours of randomization. Patients who were considered at risk of developing more severe COVID-19 were not included in the study.

Patients who did not belong to the eligible control group received a single dose of REGEN-COV that received either IV or SC. IV doses ranged from 300-2,400 milligrams (mg), but SC doses were given only at 600 or 1,200 mg.

Healthcare workers, healthcare providers, and patients were blinded to the control group and dosage, but could not be blinded to the method of administration.Researchers were primarily investigating baseline changes Viral load With NP sample for the first 7 days. In particular, researchers also looked at the number of harmful and serious adverse effects.

A total of 815 patients were included in the study. The ANCOVA model used the treatment group as a fixation effect and the baseline viral load and treatment as a covariance and adapted the data for statistical analysis.

Investigation result

Of the total of 815 patients, 523 were assigned to IV treatment and 292 were assigned to SC treatment. No serious cases of COVID-19 occurred during the study. About 90% of patients were low-risk symptomatic and the rest were asymptomatic.

Researchers found that both IV and SC doses of REGEN-COV significantly reduced viral load on day 7. The most effective reduction in viral load was seen when 2,400 mg IV was administered.

At 1,200 mg, SC and IV reduced viral load equally, and the dose given when SC was administered did not affect viral load reduction. IV administration tended to result in a steady decrease in antibody concentration over all 7 days, and SC administration continued to rise slowly until day 7, but by day 3 the REGEN-COV concentration was near maximum. Brought 3.

One patient showed a mild response but had no serious safety concerns. The other two safety issues were determined to be drug-independent.

Conclusion

The authors emphasize how the drug showed a significant reduction in viral load and rapid absorption of REGEN-COV into the body at all doses after administration by either route. The combination of no safety issues and linear and proportional pharmacokinetics for ongoing trials in patients with more severe COVID-19 or at risk of developing a more severe prognosis. It is suggested that it is safe.

High doses increased viral load reduction, but researchers showed antibody concentrations that reached 60-several hundred times the amount required to neutralize most VOCs at the lowest doses, even at low doses. It suggests that it is worth investigating.

Increasing the amount of promising drugs that are beginning to approach availability is for public health policy makers and healthcare professionals, as many VOCs are beginning to show increased ability to avoid both vaccine-induced immunity and innate immunity. I am relieved. In addition, the availability of these antivirals should enable more informed decisions about the need to reintroduce treatment and restrictions for patients.

*Important Notices

medRxiv Publish preliminary scientific reports that should not be considered definitive as they have not been peer-reviewed, guide clinical practice / health-related behaviors, and should not be treated as established information.