Antibody cocktail therapy for COVID-19 patients

Antibody cocktail therapy for COVID-19 patients. Regeneron antibody cocktail therapy reduces the risk of death or mechanical ventilation by about half.

The first antibody therapy to demonstrate antiviral effects in COVID-19 hospitalized patients. Regeneron Pharmaceuticals recently announced an encouraging preliminary data from a Phase 1/2/3 clinical trial of antibody cocktail therapy (casirivimab and imdevimab) for COVID-19 patients hospitalized with low flow oxygen. The results showed that the company’s antibody cocktail therapy passed the efficacy analysis.

The prospective design of the analysis focused on patients who have not yet developed an autoimmune response to SARS-CoV-2 (ie, no antibodies at baseline: seronegative), because previous evidence suggests that these patients are at higher risk. The main clinical purpose of this preliminary analysis is to determine whether these patients have sufficient efficacy to ensure continued trials (ie, invalidity analysis).

The results passed the invalidity analysis (one-sided p<0.3), because seronegative patients who received mixed antibody therapy had a lower risk of death or mechanical ventilation (HR: 0.78; 80% confidence interval: 0.51–1.2). According to post-mortem analysis, this benefit stems from the results that started one week after treatment, that is, antibody cocktail therapy reduces the risk of death or mechanical ventilation by about half.

The viral load of seronegative patients (n=217) was much higher than those patients who had developed their own SARS-CoV-2 antibodies (seropositive) at the time of randomization.

“These preliminary results in hospitalized patients, as well as the previously announced outpatient trial data, indicate that the antibodies produced by the patient’s autoimmune response are very important for controlling COVID-19 infection. In this trial, patients who did not enhance their autoimmune response had higher The viral load and worse clinical results; for example, in the placebo group, the mortality rate of seronegative patients is almost three times that of seropositive patients” said George D. Yancopoulos, MD, President and Chief Scientific Officer of Regeneron. “

In addition, these trial data from hospitalized and non-hospitalized patients indicate that Regeneron’s antibody mixture may compensate for the lack of endogenous antibody response by reducing the risk of virus levels and adverse clinical outcomes. Importantly, although the virological results derived from the analysis of hospitalized patients are reliable, the clinical efficacy data are based on small data sets of events and cannot be considered conclusive at this stage.

A larger trial is needed to rigorously describe this effect, and we believe the ongoing UK rehabilitation trial will provide these answers. It has recruited more than 2,000 hospitalized patients as part of a trial to evaluate the addition of an antibody cocktail to standard care compared with standard care alone. “

Both antibody cocktail doses are well tolerated. In the entire trial population, the incidence of serious adverse events was 21% in the high-dose group, 20% in the low-dose group, and 24% in the placebo group. Infusion reactions were more common in the high-dose antibody cocktail group (2.7% high-dose, 0.9% low-dose, 1.4% placebo). Two cases were discontinued due to infusion-related reactions, both of which occurred in the high-dose group.

Complete the supply of 300,000 doses of antibody drugs for the U.S. market in January 2021

In November, the Regeneron antibody cocktail was granted emergency use authorization (EUA) by the US Food and Drug Administration (FDA) for high-risk patients who have been diagnosed with COVID-19 but are not currently hospitalized. And the company has signed an agreement with the US government to complete the supply of 300,000 doses of antibody drugs to the US market in January 2021.

EUA is temporary and cannot replace the formal Biological Agent License Application (BLA) submission review and approval process. The use of antibody mixtures is still under study. A number of clinical trials are underway to evaluate its safety and effectiveness.

David Weinreich, MD, Senior Vice President and Head of Global Clinical Development of Regeneron, said: “We thank patients and researchers around the world for their support in advancing the Regeneron antibody cocktail trial under very challenging conditions.”

“Globally, more and more patients are hospitalized due to COVID-19, which has had catastrophic consequences for these patients, their families and those caring for them, which highlights the need for effective treatment. We plan to Regulators share these latest data.”

In addition to the two inpatient trials (company sponsored and the UK recovery trial), the antibody cocktail is currently being studied in a Phase 3 clinical trial for the treatment of non-hospitalized patients and for the prevention of infecting people with family contacts in the COVID-19 Phase 3 clinical trial.

According to an agreement with the US government, Regeneron is producing approximately 300,000 doses (2,400 mg) for EUA outpatient use. The company expects to complete the production of these doses as scheduled in January 2021, and is discussing more doses with the US government.

About Regeneron clinical trials in hospitalized patients

The analysis includes patients included in the Phase 1/2 of the trial, which aims to evaluate the clinical outcome, safety and antiviral activity of anti-COVID-19 casirivimab and imdevimab antibody cocktail therapy. The patients were randomized 1:1:1 to receive a one-time injection of 8000 mg antibody cocktail (high dose), 2400 mg antibody cocktail (low dose) or placebo. All patients participating in the trial were hospitalized due to laboratory-confirmed COVID-19 requiring low-flow oxygen, and all received other standard care required.

About Regeneron antibody cocktail

Casirivimab and imdevimab are a mixture of two monoclonal antibodies (respectively called REGN10933 and REGN10987), which are specifically designed to block the infectivity of the SARS-CoV-2 virus that causes COVID-19.

To develop this new drug, Regeneron scientists evaluated thousands of fully human antibodies produced by the company’s VelocImmune® mice. These mice have been genetically modified to have a human immune system, they have been genetically modified to have a human immune system, and Antibodies identified from patients recovering from COVID-19.

Regeneron will continue to increase the internal production of casirivimab and imdevimab, and cooperate with Roche to increase its global supply from 2021.

If the treatment is granted by clinical trials and regulatory approval that proves to be safe and effective, Regeneron will be produced and distributed in the United States, and Roche will develop, produce, and distribute outside the United States. Once the two companies have full production capacity in 2021, it is expected to have at least 2 million annual therapeutic doses.

(source:internet, reference only)

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