Prevention truly is better than cure when it comes to infectious diseases, and that is all the more true for COVID-19. Like other viruses, the fight against COVID-19 currently suffers from a lack of viable treatments – the available vaccines are impressively effective at stopping cases, but serious infections are still killing people in many corners of the globe. Once infected, most therapies to treat it involve simply keeping the patient oxygenated and stable until their immune system can fight off the virus particles within their body. Unfortunately, this is not always successful, and with uncontrollable case numbers in many nations as the pandemic continues, a treatment for COVID-19 infection is desperately needed.
Once again Pfizer hopes to rise to the occasion. Currently, underway in Brussels, Belgium is a Phase 1 clinical trial into the first pill designed to treat COVID-19 infection. Targeting a specific enzyme that the virus needs to replicate within host cells, Pfizer hopes the pill – eloquently named PF-07321332 – will combat infection as soon as it first appears.
“Tackling the COVID-19 pandemic requires both prevention via vaccine and targeted treatment for those who contract the virus. 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,” said Mikael Dolsten, MD, PhD., Chief Scientific Officer and President, Worldwide Research, Development and Medical of Pfizer, in a statement when the trial initially began.
“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. At the same time, Pfizer’s intravenous antiviral candidate is a potential novel treatment option for hospitalized patients. Together, the two have the potential to create an end to end treatment paradigm that complements vaccination in cases where disease still occurs.”
PF-07321332 is a protease inhibitor, which directly prevents the production of virus particles within a host. If the virus cannot reliably replicate into high numbers, it stops the infection from taking hold and causing damage. Protease inhibitors are widely used in the treatment of HIV and Hepatitis C, but despite proving effective at combatting COVID-19 and other coronaviruses in cell culture experiments, they have not yet been proven to be safe and effective in humans. Alongside PF-07321332, Pfizer is also investigating PF-07304814, an intravenously administered protease inhibitor that is currently being trialed in hospitalized patients.
The PF-07321332 clinical trial is still underway, involving up to 60 healthy adult volunteers, and aims to end on the 25th of May. The trial is testing for safety and tolerability and looking at how the compound moves through the body of healthy volunteers. Further trials will have to be done on larger groups to test for safety and efficacy before it could be labeled as a therapeutic agent against SARS-CoV-2.