Pfizer taps HIV, hep C antiviral research for COVID-19 pill trial

Pfizer HQ
(By Norbert Nagel, Mörfelden-Walldorf, Germany (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons)

Pfizer has already seen major success with its BioNTech-partnered COVID-19 vaccine, but, now, the Big Pharma is hoping to add to the arsenal with a pandemic pill using old antiviral technology.

The U.S. giant said it has kick-started a new, early-stage U.S. trial of an oral anti-COVID-19 med known as PF-07321332, which should be given to patients as soon as they see signs of infection. The theory is this will dampen the virus’s ability to cause severe disease or death.

Current antibody drugs from the likes of Eli Lilly and Regeneron are given through an infusion and have struggled to reach enough patients, with new variants also causing concern that they can outrun some of the original antibodies.

Pfizer is using an older, tried and tested method: PF-07321332 is a protease inhibitor that has been used for many years against a range of infections including HIV and hepatitis C. The hope is this will be able to hit back at the virus and with few side effects, given we already have many years’ worth of data on this tech.

It also can be prescribed and taken outside of a secondary care setting, rather than via infusion clinics or in hospitals, as the current crop of antibody drugs have to be. It follows similar work from the likes of Merck and biotech partner Ridgeback and their midstage effort molnupiravir as well as Roche and Atea Pharmaceuticals’ antiviral AT-527.

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Drugs against the virus have, however, had a tough time in testing, with failures and setbacks for a number of experimental and repurposed drugs over the past year slowing attempts for a knockout vaccine-therapeutic approach to stop the virus in its tracks and prevent those with the disease from getting very sick.

As well as a pill, Pfizer is also working on a study using an intravenously administered antiviral candidate in another early-stage trial, but this one is for hospitalized COVID-19 patients.

“Tackling the COVID-19 pandemic requires both prevention via vaccine and targeted treatment for those who contract the virus,” said Pfizer’s chief scientific officer, Mikael Dolsten, M.D., Ph.D., in a statement.

“Given the way that SARS-CoV-2 is mutating and the continued global impact of COVID-19, it appears likely that it will be critical to have access to therapeutic options both now and beyond the pandemic.”