Covid-19 antibody therapies show promising early results in separate trials

Eli Lilly, AbCellera, and NIAID have worked together to create an antibody they think may help treat Covid-19.

Days after Eli Lilly and Company said it would stop a trial of its Covid-19 antibody therapy in hospitalized patients because it was not effective, the company on Wednesday published promising interim results from a trial involving patients with mild and moderate Covid-19.

Also on Wednesday, biopharmaceutical company Regeneron reported its monoclonal antibody cocktail treatment helped people with mild and moderate Covid-19.

There are at least 78 monoclonal antibody treatments for Covid-19 in various stages of development in labs around the world, but those made by Lilly and Regeneron have been among the most closely watched. Both Lilly and Regeneron have already applied to the US Food and Drug Administration for emergency use authorizations that would open up their antibody treatments to more people with Covid-19.

Published results from Eli Lilly

Results from Eli Lilly were published Wednesday in the New England Journal of Medicine. The company's interim analysis showed its monoclonal antibody treatment seemed to lower the risk of hospitalization and ease some symptoms in a small number of patients with a mild to moderate case of Covid-19.

The Phase 2 trial involved 452 patients, some of whom received the treatment and some of whom received a placebo, which does nothing. Only 1.6% of patients who took the treatment had symptoms progress enough that they had to be hospitalized or seek care at the emergency room. For patients who got the placebo, it was 6.3%.

For patients in higher risk categories -- those who were 65 years or older or obese -- 4% who got the treatment were hospitalized. For those who got the placebo, it was 15%. Those who received the treatment also had slightly less severe symptoms than those who got the placebo.

The study was primarily testing to see if the therapy eliminated the virus by day 11. The vast majority of patients had eliminated or had little trace of the virus by then. While the hospitalization data was a secondary endpoint, study co-author Dr. Peter Chen characterized the difference as "dramatic" and "meaningful."

More research needs to be done in a larger number of patients to determine if the therapy, known as bamlanivimab, really works, but scientists not involved in the trial said these early results were "encouraging."

"The devil will be in the details, and of course, in the cost/benefit ratio with these very expensive drugs," Dr. Jeanne Marrazzo, the director of the division of infectious diseases at the University of Alabama at Birmingham School of Medicine, said in an email. Marrazzo did not work on the trial.

Wednesday, Lilly announced it had struck a $375 million deal with the government for 300,000 vials of the antibody treatment, pending US Food and Drug Administration emergency use authorization, to be delivered in the two months after. Lilly applied for an emergency use authorization in October. The company said it planned to have 100,000 doses ready to ship within days of approval and would manufacture a million doses by the end of 2020. The treatment would be provided to patients at no cost.

On Monday, Eli Lilly announced another trial of its antibody therapy was stopped. The trial involving hospitalized patients was stopped because results showed the treatment did not help patients with severe symptoms.

Lilly's larger trial with mild-to-moderate Covid-19 patients is still underway, as is a trial testing the therapy in long-term care facilities. Another trial is testing the monoclonal antibody in combination with another monoclonal antibody. That trial is also in patients with mild to moderate disease.

Results from Regeneron

For Regeneron's antibody therapy, the company said results from its later-stage trial showed it reduced the need for medical visits among Covid-19 patients with mild to moderate disease.

The company made the announcement Wednesday in a news release. The details of the data were not published in a medical journal, nor were they peer-reviewed.

Regeneron said the treatment significantly reduced viral load and reduced the need for a patient to go to the hospital, emergency room, urgent care or doctor's office.

The analysis involved nearly 800 patients. Patients on the treatment had on average a greater-than-10-fold reduction in viral load by day 5 than those taking a placebo, which does nothing. Patients with the higher viral load at baseline got a bigger benefit from the therapy. The therapy reduced Covid-19 related medical visits by 72% in patients with one risk factor for severe disease, the company said.

"Today's analysis, involving more than 500 additional patients, prospectively confirms that REGN-COV2 can indeed significantly reduce viral load and further shows that these viral reductions are associated with a significant decrease in the need for further medical attention," Dr. George D. Yancopoulos, president and chief scientific officer of Regeneron, said in a statement. "We continue to see the strongest effects in patients who are most at risk for poor outcomes due to high viral load, ineffective antibody immune response at baseline, or pre-existing risk factors."

The results didn't show any significant difference between the high and low dose of the treatment and because of that Regeneron is reviewing the dosage it will use in the ongoing outpatient trial, since there is a limited supply of the treatment.

Regeneron said it has shared the results with the FDA as part of the paperwork submitted in its request for emergency use authorization. The company said it will also submit these results for publication.

In July, Regeneron struck a $450 million deal for the government to deliver treatment or prevention doses to Americans at no cost once it is approved. The company started scaling up manufacturing of the antibody treatment in spring.

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