Pfizer Phase 3 Interim Report

Updated on Friday, November 20th 2020

Overview

On Monday November 9th, the pharmaceutical and biotechnology companies, Pfizer and BioNTech, announced an interim report on the Phase 3 clinical trial of their COVID-19 vaccine. The report indicates that their two-dose vaccination is about 90% effective in preventing a SARS-CoV-2 infection. Although the study has not been concluded, this data brings into a clearer view, the end of the COVID-19 pandemic. This article will provide background into the BNT162b2 vaccination, deeper understanding of the interim report, a tentative timeline, and other implications of this progress.

Background on BNT162

Pfizer and BioNTech have developed a vaccine, BNT162, which is mRNA based. Similar to Moderna’s vaccine, the mRNA is bound inside lipid nanoparticles in order to protect and help the material enter the body’s cells before instructing it to begin making viral proteins. The immune system will then recognize the foreign particles and begin a response to protect against SARS-CoV-2 without introducing live viruses. Unlike Moderna, Pfizer and BioNTech have expanded their testing and vaccine to include 3 different mRNAs and are testing them individually. 

Pfizer and BioNTech designed their testing process as one large clinical trial with 3 rounds, Phase 1/2/3. Phase 1 testing of BNT162 began in late April when participants were randomly treated with two doses of a placebo or one of the two BNT162 candidates: b1 and b2 – each holds mRNA that instructs the production of different SARS-CoV-2 proteins. Additionally, the companies also tested elevation of dosage.  

The results of Phase 1 indicated that BNT162b2 elicited less incidence and severity of symptoms in older adults than BNT162b1, meanwhile both candidates elicited similar dose-dependent responses in younger participants. Pfizer and BioNTech chose BNT162b2 as the candidate for evaluation in Phase 3 of the clinical trial, where testing expands on cohorts and efficacy of the vaccine at a mid-dose level.

Interim Report from Phase 3

Pfizer announced results from an interim study conducted by an external, independent Data Monitoring Committee (DMC). The DMC stated the BNT162b2 had a 90% efficacy on preventing SARS-CoV-2 infections in volunteers who had no history or evidence of a prior infection. The DMC determined the 90% efficacy based on the number of COVID-19 cases in the BNT162b2 compared to the placebo group.

BNT162b2 has since shifted to a 95% efficacy after Pfizer met all Phase 3 primary efficacy endpoints. With this data, Pfizer has now met the requirements to submit a request for Emergency Use Authorization (EUA) with the Food and Drug Administration (FDA).

Alongside the study results, Pfizer indicated that the vaccine efficacy could vary as the trial continues. In comparison, the flu vaccine efficacy ranges from 40% to 60% depending on the demographic. Therefore, even a considerable decrease in efficacy would still allow BNT162b2 to have an important role in ending the COVID-19 pandemic. Furthermore, the study also did not report any serious safety concerns, yet still recommends for Pfizer and BioNTech to continue collecting additional safety and efficacy data. This data will then be administered to regulatory committees around the world.

Tentative Timeline

Before BNT162b2 can become available to the general public, the vaccine must get approval from the FDA. And prior to the approval, Pfizer must acquire a median of two months data after the final (second) dose of the vaccine. Along with the efficacy data, Pfizer and BioNTech are acquiring safety and manufactory data to propose an argument to the FDA in order to get approval for Emergency Use Authorization. 

On Friday, November 20th, Pfizer announced their request to the FDA for Emergency Use Authorization. Over multiple weeks, the FDA will hold meetings to listen to Pfizer’s argument, analyze their results, and discuss as an administration in order to collectively make the best decision on permitting BNT162b2 for emergency use.

If approved, the companies hope to globally produce 50 million vaccine doses by the end of 2020 and 1.3 billion doses by the end of 2021.

As for public distribution, neither President Trump nor President-elect Biden have outlined logistical vaccine distribution campaigns. However, President-elect Biden has committed to investing $25 billion into manufacturing and distribution in order to guarantee a zero-cost vaccine for every American. 

*Visit the CDC’s FAQ page on COVID-19 Vaccination

Positive Outcomes

The results from the interim report are a clear encouragement not only for Pfizer and BioNTech, but also the rest of the world as it shines light on the successes of science and makes the end of the pandemic a clearer reality.

First, it’s becoming more apparent that there will likely be multiple successful COVID-19 vaccines. BNT162b2, although using a different mechanism, ultimately focuses on the spike protein of SARS-CoV-2, like most other COVID-19 vaccines in development. This indicates that other pharmaceutical companies, such as Johnson & Johnson, Moderna, Sinovax, etc.– will all likely succeed in preventing infections.

Second, there’s hope for a new class of vaccinations that utilizes mRNA. Currently, there is no mRNA vaccine on the market, opening a huge field for medical research. Moreover, the pharmaceutical company, Moderna, is assured that their vaccine can be successful as they too are developing an mRNA vaccine for COVID-19.

Lastly, having such high efficacy can have a large influence in getting a population vaccinated. Many people believe that vaccines don’t protect as much as they claim to do. And with that, there’s a fear that COVID-19 vaccines aren’t properly developed and tested due to such a short timeline. However, as election polls show, more than half the nation views the COVID-19 pandemic as the most important issue and a 90% efficacy might be enough to push people to receive a COVID-19 vaccine.

Challenges

By likely being the first COVID-19 vaccine, BNT162b2 doesn’t come without its challenges. 

The vaccine doses are required to be stored at an extremely low temperature of -94˚F (-70˚C). Although many hospitals and research labs are suited with freezers that reach these temperatures, this makes distribution hard, specifically distribution in rural areas and developing countries that don’t have access to such technology. Because of this, there's a cause for concern about unequal access to the COVID-19 vaccine when it becomes readily available. Therefore, multiple successful COVID-19 vaccines need to be produced in order to meet the needs and conditions of rural and developing regions.

Unanswered Questions

Although these results reveal more about the COVID-19 pandemic, there are still questions left unanswered. 

First, due to the shortened timeline of vaccination clinical trials, Pfizer, along with other pharmaceutical companies, won’t know the lasting immunity of their vaccines until well after they’ve been distributed. However, some information on lasting immunity might come from volunteers who received the vaccine in earlier stages (March–April) of the clinical trials.

Second, there’s no clear understanding on whether BNT162b2 can help prevent the spread of SARS-CoV-2 when the person is experiencing minimal to no symptoms. In other words, does the vaccine also function as a transmission blocker?

Third, the interim report did not indicate the severity of illness in the volunteers who had COVID-19. There’s questions as to whether BNT162b2 can, if not prevent total illness, at least prevent more severe forms of COVID-19.

Lastly, the specific efficacies in certain demographics are unknown. The interim report did not include information as to the ages of the volunteers who had COVID-19, bringing into question a skewed efficacy that doesn’t fit for the elderly demographic.

Sign up for CScreener and perform an easy and safe health screening for your employees and students.