The Fight Continues as Therapies for COVID-19 Race Through Development
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While modern-day science has provided the world with highly effective vaccines to fight the COVID-19 pandemic, researchers have had less luck finding effective treatment options for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Rising cases of the Delta variant, coupled with less-than-ideal vaccination rates, have made finding these post-exposure COVID-19 therapies of utmost importance.
In the U.S., a total of 10 drugs for COVID-19 have either been cleared or recommended for use. Two of those therapies, however, were later found to not provide any benefit and their authorizations were revoked. Shipments for a third drug, an antibody cocktail from Eli Lilly comprising bamlanivimab and etesevimab, were paused last month because U.S. regulators found it wasn’t effective against new and emerging SARS-CoV-2 variants.
Although vaccines offer the best hope for ending the COVID-19 pandemic, vaccination efforts are slowing worldwide, and many resource-poor countries and regions are struggling to acquire doses. Currently authorized COVID-19 vaccines have certainly demonstrated high efficacy in late-stage trials, but none are 100% effective against preventing infection.
As such, clinical trials are currently evaluating over 225 drug therapies, including novel agents and drugs already approved for other indications. President Biden is lending support to the cause, saying recently his administration would pay $3.2 billion to support the development of antiviral pills against COVID-19.
Some large pharmaceutical companies are racing to develop their own antiviral pills, with Merck and Pfizer currently in the lead. These companies are evaluating their antiviral therapies, each of which can be taken at home early in the course of infection.
Merck’s pill, which is in development under a collaboration with Ridgeback Biotherapeutics, hit a snag earlier this year when it failed to show benefit in patients who were hospitalized. Currently, researchers are evaluating the efficacy of Merck therapy in newly infected patients.
Pfizer launched a 60-person Phase I trial of its novel oral antiviral pill PF-07321332 in late March. “We have designed PF-07321332 as a potential oral therapy that could be prescribed at the first sign of infection, without requiring that patients are hospitalized or in critical care,” according to a statement made by Pfizer’s Chief Scientific Officer and President of Worldwide Research, Development and Medical, Mikael Dolsten, M.D., Ph.D.
Remdesivir is perhaps the most well-known antiviral agent that has been studied extensively in COVID-19-related research. Since 2014, researchers from the University of North Carolina and Vanderbilt University, alongside help from the U.S. government, have been collaborating with Gilead Sciences to evaluate the agent's efficacy against coronaviruses.
The well-known antiviral therapy remdesivir was shown to be helpful in the early stages of infection in infected mice, but at the time, the agent wasn’t easy to administer in humans. Remdesivir was authorized in the U.S. in May 2020 and was later given full approval, but patients given the therapy tend to recover slowly.
Late last month, Pardes Biosciences went from stealth mode to SPAC with its oral antiviral drug currently in development for COVID-19. The company merged with special purpose acquisition company FS Development Corp II, a deal backed in part by Gilead Sciences.
Pardes’ drug candidate, dubbed PBI-0451, inhibits essential virus protein found in SARS-CoV-2. “The emergence of novel variants of increasing pathogenicity, such as the Delta variant, reinforces the need for new therapies that can be easily and rapidly deployed globally,” said Foresite Capital’s founder and CEO, Jim Tananbaum, M.D., in a statement.