Pfizer Begins to Dose Patients in its Oral Covid-19 Drug Trial

Pharmaceutical giant Pfizer has now started to dose patients in its oral COVID-19 drug trial.

The company said on Wednesday that it had started dosing in a mid-to-late-stage trial of its oral antiviral therapy for COVID-19 in non-hospitalized, symptomatic adult patients.
In the mid-to-late-stage trial that has 1,140 participants, Pfizer would study the therapy, PF-07321332, in combination with a low dose of ritonavir, which has been used with other antivirals too.

PF-07321332 is designed to block the activity of a key enzyme that is needed for the coronavirus to replicate.

the only approved antiviral treatment for COVID-19 in the U.S. is Gilead Sciences Inc’s remdesivir.

Merck and partner Ridgeback Biotherapeutics are also studying molnupiravir in a late-stage trial in non-hospitalized patients to see if it reduces the risk of hospitalization or death.

Pfizer said earlier in the summer that if the PF-07321332 trial was successful, it would file for a potential emergency use authorization in the fourth quarter.

Per the company’s press release, Protease inhibitors, like PF-07321332, are designed to block the activity of the main protease enzyme that the coronavirus needs to replicate. Co-administration with a low dose of ritonavir is expected to help slow the metabolism, or breakdown, of PF-07321332 in order for it to remain in the body for longer periods of time at higher concentrations, thereby working continuously to help combat the virus. Ritonavir has previously been used in combination with other antivirals to similarly inhibit metabolism.

This study is part of a global clinical development program, consisting of multiple ongoing and planned clinical trials to evaluate this early-intervention, outpatient therapeutic candidate for potential use in a broad population of patients. The first registrational trial in this program, a pivotal Phase 2/3 study of PF07321332/ritonavir in non-hospitalized, symptomatic adult participants who have been diagnosed with SARS-CoV-2 infection and are at increased risk of progressing to severe illness, began enrollment in July 2021.

If successful, PF-07321332/ritonavir has the potential to address a significant unmet medical need, providing patients with a novel oral therapy that could be prescribed at the first sign of infection, without requiring hospitalization

Disclaimer: We have no position in any of the companies mentioned and have not been compensated for this article.