Pfizer Says New Anti-Viral Drug Combination Cuts Risks Of Serious COVID-19 By 89% 
Pfizer’s experimental pill works by inhibiting replication of SARS-CoV2 virus.

Pfizer Friday announced that its experimental COVID-19 oral antiviral drug PAXLOVID™ reduced risks of hospitalization and death by 89% among patients who received the drug within the first three days of their illness. The company said it had stopped its Phase 2/3 trial on the drug owing to the success rate seen in an interim analysis of 1,219 adults enrolled in the study – who also had chronic health conditions placing them at higher risk of severe COVID.  

Pfizer is the second pharma firm, after Merck Sharp & Dohme (Merck), to announce highly promising results for an oral drug treatment that reduces serious COVID-19 illness – although the Pfizer results were even more stunning.

PAXLOVID™ has the potential to eliminate up to nine out of ten hospitalizations, Albert Bourla, Chairman and Chief Executive Officer, Pfizer, said in a press release

It’s a gamechanger,” Pfizer CEO Albert Bourla told @megtirrell about its Covid-19 antiviral drug. “This is a fantastic demonstration of the power of science.”

If approved for emergency use by the United States Food and Drug Administration (US FDA), PAXLOVID™ would become the first oral COVID antiviral of its kind. The novel treatment includes a newly- designed SARS-CoV-2-3CL protease inhibitor used in combination with a common anti-HIV drug, ritonavir.

Bourla told CNBC that the filing for the drug is expected to be submitted before the U.S. Thanksgiving holiday on Nov. 25.

Pfizer’s results more impressive than Merck’s

The Pfizer announcement follows Merck’s announcement last month that it’s new oral pill, molnupiravir,  had reduced the risks of hospitalization and death by some 50% among people with mild or moderate COVID.

The Merck pill, which was approved by UK regulators last week, introduces errors into the genetic code of the SARS-CoV2 virus that it targets, slowing virus replication.

Pfizer’s reported  results were even more impressive, however.  Based on a primary analysis of interim data from 1,219 at-risk adults who were enrolled by September 29, 2021, only three people administered the drug within three days of sympton onset were hospitalized through day 28 of their illness, with no deaths. In the control group, 27 people were hospitalized, with seven subsequent deaths.

When the company decided to stop recruiting more patients, their enrollment had reached 70 percent of the planned 3,000 patients across North and South America, Europe, Africa, and Asia.

Pfizer drug is based upon a novel protease inhibitor, PF-07321332, that blocks the activity of the enzyme that the coronavirus needs to replicate. Co-administration of ritonavir means that protease inhibitor remains active in the body for longer periods of time to combat the virus. Treatment involves the administration of three PAXLOVID™ pills, twice a day, for five days. 

Pfizer says it will also ensure equitable access to new drug formulation

While Merck’s molnupiravir pill is set to be licensed for generic production in most low- and middle-income countries, Pfizer said that it will offer PAXLOVID™ worldwide, through a tiered pricing approach – while maintaining control of its IP. 

Last week, Merck and the Medicines Patent Pool signed an agreement that paves the way for MPP to sign contracts with generic drug manufacturers to produce and sell their treatment molnupiravir at discounted prices to more than 105 countries worldwide, once the drug receives approval by the World Health Organization.

Pfizer, in contrast, said that its tiered pricing would be “based on the income level of each country to promote equity of access across the globe.

“High and upper-middle income countries will pay more than lower income countries,” Pfizer said, adding that it had already entered into advance purchase agreements with “multiple countries and is in negotiations with several others” – without naming which.

“Pfizer has also begun and will continue to invest up to approximately $1 billion to support the manufacturing and distribution of this investigational treatment, including exploring potential contract manufacturing options to help ensure access across low- and middle-income countries, pending regulatory authorization.”

Image Credits: Wikimedia Commons, .

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