Pfizer COVID-19 Treatment Pill: What You Need to Know

Illustration of a pill bottle.

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Key Takeaways

  • Pfizer is developing a new oral drug to treat COVID-19 that could be available by the end of the year.
  • The treatment is a protease inhibitor, a class of drug used to treat HIV and hepatitis C.
  • The drug could potentially be used against other coronaviruses, in addition to COVID-19.

A new COVID-19 treatment may soon be on the market. Pfizer is developing a new oral drug to treat COVID-19. People would be able to take the drug at home, possibly eliminating the need to visit a hospital to receive treatment for the disease.

If clinical trials go to plan, a user could take the oral drug at the first sign of illness, decreasing their chance of becoming seriously ill with the disease. Pfizer says the drug could be available by the end of the year and may be able to reduce burden on hospitals.

“Tackling the COVID-19 pandemic requires both prevention via vaccine and targeted treatment for those who contract the virus," Mikael Dolsten, MD, PhD, Chief Scientific Officer and President of Pfizer said in a statement. "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."

Pfizer's New Oral Drug

The company developed the first U.S. authorized COVID-19 vaccine in partnership with BioNTech. Now they're making strides in COVID-19 treatment. The new drug, called PF-07321332, is currently undergoing clinical trials.

The company is also developing an antiviral COVID-19 treatment that would be administered intravenously. This option would be available for hospitalized patients and is currently in phase 1b of multi-dose clinical trials.

The Pfizer pill falls into a class of drugs called protease inhibitors, which include oral treatments for pathogens like HIV and hepatitis C.

How Protease Inhibitors Work

To infect a person’s body, SARS-CoV-2, the virus that causes COVID-19, must penetrate cells of the person's body. Once inside, the virus uses the cells to make copies of its genetic information so it can create more of the virus.

Proteases are enzymes that play an important role in this process. The virus uses this enzyme as a kind of molecular scissor that can chop up long proteins, enabling the virus to replicate itself in the cell. But when proteases are met with molecules called inhibitors, they become blocked and can no longer do their job.

“This is actually essential,” Alejandro Chavez, MD, PhD, assistant professor of pathology and cell biology at Columbia University, tells Verywell. “If it doesn't chop its protein into smaller pieces, the proteins basically don't work.”

Chavez is part of a team of researchers that identified three compounds that could act as inhibitors of the main protease, published in the journal Nature Communications in April. The most important protease to target when combating SARS-CoV-2 is called 3CL. Though the virus contains one other protease, 3CL does most of the heavy lifting when it comes to breaking up proteins.

The Pfizer drug targets the 3CL protease by introducing new inhibitors into the body. If these molecules can prevent the virus from replicating, the infected person is less likely to become seriously sick.

“Some of these inhibitors against 3CL proteases have been given to animals," Chavez says. "And those animals show rescue from disease—it essentially saved their lives."

What This Means For You

Right now, the only approved treatment against COVID-19 is remdesivir, which only treats those with severe cases of COVID-19 that require hospitalization. Pfizer's oral drug could be the first drug available to treat COVID-19 at home.

How Might It Fare Against Variants?

But how will this drug fare against COVID-19 variants?

When developing vaccines, scientists are mindful of how well their vaccines will be able to protect the body against different viral variants. The SARS-CoV-2 virus has mutated to exhibit differences in the spike protein—the part of the virus which helps it latch onto healthy cells.

The oral drug deals with a different component of the virus’s life cycle. By inhibiting the protease, scientists think this antiviral treatment can stop the virus from replicating, regardless of the variation in its spike protein. Protease inhibitor drugs and COVID-19 vaccines, then, will likely support each other in the goal of minimizing how well the virus can infect the body.

“When you hit a virus with three different molecules, each attacking different areas of the virus, then it becomes very challenging for it to solve that problem,” Chavez says.

Additionally, stopping the 3CL protease seems to be effective at preventing viral replication beyond SARS-CoV-2. According to the company statement, the Pfizer drug was “potent” as an in vitro anti-viral agent for multiple coronaviruses, suggesting it may be used against COVID-19 as well as future coronavirus threats.

Though protease inhibitors have proven largely effective in combating pathogens like hepatitis C and HIV, Chavez says there are lessons to be learned from treating those diseases. Over time, viruses may recognize these inhibitors and evolve to become resistant to them. To make protease inhibitor drugs more useful in the long-term, it may be best to take them in combination with other medications, rather than as a stand-alone drug.

What This Might Mean for COVID-19 Treatment

The Pfizer drug was first tested using intravenous delivery. Chavez says it’s more challenging to create a treatment that can be delivered orally. But developing an option that would allow people to self-treat at home would make it easier to treat a larger population.

“In the end, the drug either going to inhibit protease or not,” Chavez says. "But the mechanism of delivery can help with ease of use.”

Dolsten says, “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.”

Pfizer CEO Albert Bourla told CNBC in April that he is optimistic that the medication could be approved and available “I hope by the end of the year.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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  1. Iketani S, Forouhar F, Liu H, et al. Lead compounds for the development of SARS-CoV-2 3CL protease inhibitors. Nat Commun. 2021;12(1):2016. doi:10.1038/s41467-021-22362-2