Pfizer Launching New Study to Test Oral Antiviral for COVID-19

The next frontier in COVID-19 treatment is oral antiviral medicines, and Pfizer is the latest company to launch a new trial in that area.

Pfizer yesterday announced a new phase 2/3 study on a novel COVID-19 antiviral candidate in adults. The new study will evaluate novel protease inhibitor — PF-07321332 co-administered with a low dose of ritonavir (an antiviral focused on HIV infection) — for prevention of illness in adults living in the same household as someone with COVID-19.

Merck, Roche and Gilead Sciences are also racing to develop oral antivirals to treat COVID-19 (DID, Sept. 24).

Pfizer’s third study on the candidate is looking to enroll 2,660 healthy adult participants, said the company.

The best-case scenario if trials go well and the candidate is approved: The drug would be administered at the first sign of infection with, or exposure to, SARS-CoV-2, without requiring patients to be hospitalized, the company said.

“If successful, we believe this therapy could help stop the virus early — before it has had a chance to replicate extensively — [before] the onset of infection in others,” said Mikael Dolsten, Pfizer’s chief scientific officer.

As part of the same series of trials, Pfizer is looking at the candidate in SARS-CoV-2 infected patients who are at high risk of severe illness, including hospitalization or death, which began in July, and another in infected patients who are at standard risk, those who do not have risk factors for severe illness, which began in August. — Suz Redfearn