In-Depth: Pfizer's antiviral COVID pill cut hospitalizations up to 89 percent

Pfizer antiviral pill for COVID-19
Posted at 6:05 PM, Nov 05, 2021
and last updated 2021-11-05 21:27:14-04

SAN DIEGO (KGTV) — A clinical trial of Pfizer’s experimental pill for COVID-19 showed the drug cut hospitalizations by up to 89 percent, a finding that doctors said could be a turning point in the pandemic if confirmed by federal regulators.

Pfizer said Friday it would seek emergency authorization from the Food and Drug Administration in the coming weeks. The pill will be sold under the brand name Paxlovid.

Currently authorized treatments for COVID require an IV or an injection. Throughout the pandemic, the “holy grail” for drugmakers and physicians alike has been an easy-to-use pill that could save lives.

Pfizer’s clinical trial began in July. Based on results from about 1,200 volunteers, the study showed the pill reduced the risk of a COVID hospitalization by 85 percent if given within five days of symptoms.

If the pills were given sooner, within three days, the drug was 89 percent effective.

No one who got Paxlovid died compared to 10 COVID deaths among people who got the placebo. The results were so compelling, an independent review board asked Pfizer to end the trial early.

“The impact is game-changing, frankly,” said UC San Francisco infectious disease expert Dr. Peter Chin-Hong. “It’s shown to be highly, highly effective. Beyond everyone’s wildest dreams.”

Patients took three pills twice per day for five days. Pfizer’s drug is actually two drugs in one, said UC San Diego infectious disease specialist Dr. Robert Schooley.

“One of the drugs is ritonavir, which is a drug that we’ve used for HIV for a long time. And it’s used not because it has any impact on coronavirus, but because it increases the levels of this Pfizer drug that does have the impact in the bloodstream,” he said.

Pfizer released limited details on side effects, but it said more people had side effects after the placebo than the drug itself.

The news comes about one month after Merck announced its oral antiviral molnupiravir cuts the risk of hospitalization by about 50 percent when given with five days.

The Merck and Pfizer drugs target different parts of the viral process.

“One can even imagine a situation like in HIV, like in hepatitis C, where the combination of both drugs might even be more potent,” said Dr. Chin-Hong. “But you know, 89 percent is pretty good as it gets.”

While these pills are important, doctors say they do not replace the need for vaccination. The pills are administered after someone is infected and develops symptoms. Even in cases with mild symptoms, the rate of long COVID of surprisingly high.

The definition of long COVID can vary between studies, but recent research shows between one-quarter and one-third of mild cases result in lingering symptoms. One study by the University of Arizona found 67 percent of people with mild or moderate COVID-19 infection developed symptoms lasting 30 days or more.

Antibodies produced by vaccination can stop the virus before it infects cells.

“It’s better not to have an automobile crash than to need a body shop,” said Dr. Schooley.

The FDA will review Merck’s drug on November 30. It could begin rolling out in early December.

Pfizer said it planned to apply for emergency use by Thanksgiving. The drug could hit pharmacy shelves in late December or early next year, Schooley said.