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Pfizer’s COVID-19 Treatment Reduces Disease by 37% Post-Exposure

In other COVID news, GSK submits a biologics license application for its COVID-19 vaccine and Novavax requests to expand its vaccine authorization in Great Britain.

By
  • Samantha McGrail
Published: 11 May 2022

Pfizer recently announced that its COVID-19 treatment, Paxlovid reduced disease by 32% and 37% in adults for 5–10 days, respectively, compared to placebo.  

The Phase 2/3 EPIC-PEP study evaluated Paxlovid for post-exposure prophylactic use in 2,957 asymptomatic adults with a negative COVID-19 rapid antigen test result. Each patient was randomized to receive Paxlovid for 5 days followed by a placebo for 5 days or Paxlovid for 10 days followed by a placebo for 10 days.  

The trial’s primary endpoint was reducing the risk of confirmed and symptomatic COVID-19 infection in adults who were exposed to the virus through household contact. This endpoint was not met.  

Available safety data for Paxlovid was generally consistent in over 3,500 Paxlovid-treated patients across EPIC-HR, EPIC-SR, and EPIC-PEP studies. In this study, the safety profile was generally consistent when the drug was used for 5 or 10 days.  

Analyses of all secondary endpoints and sub-groups are ongoing, and Pfizer will include the results in all publications or presentations of the final study results.  

“We designed the clinical development program for Paxlovid to be comprehensive and ambitious with the aim of being able to help combat COVID-19 in a very broad population of patients,” Albert Bourla, chairman and CEO of Pfizer, said in the announcement.  

“While we are disappointed in the outcome of this particular study, these results do not impact the strong efficacy and safety data we’ve observed in our earlier trial for the treatment of COVID-19 patients at high risk of developing severe illness, and we are pleased to see the growing global use of Paxlovid in that population,” Bourla continued.  

Currently, Paxlovid is approved or authorized for conditional or emergency use in over 60 countries globally to treat high-risk COVID-19 patients.  

GSK Submits BLA for COVID-19 Vaccine Candidate  

GSK and SK bioscience recently submitted a biologics license application (BLA) to the Korean Ministry of Food and Drug Safety (KMFDS) for SKYCovione, a recombinant protein-based COVID-19 vaccine. 

SK bioscience conducted a Phase 3 clinical trial in 4,037 adults over 18 years of age across six countries: Thailand, Vietnam, New Zealand, Ukraine, the Philippines, and South Korea. In all trials, SKYCovione demonstrated superior neutralizing antibody titers over AstraZeneca’s Vaxzevria. 

Researchers also found that the vaccine showed a superior neutralizing antibody response against the SARS-CoV-2 parental strain, 2.93 times that of a control vaccine two weeks after the second dose.  

And 98.06% of patients seroconverted in the SKYCovione group, while 87.30% seroconverted in the control group. Notably, the antibody conversion rate was over 95% compared to the control vaccine in subjects 65 and older.  

“As the COVID-19 pandemic continues to evolve, a variety of vaccines will be needed to meet the health needs across the globe, including temperature-stable vaccines like the SK/GSK vaccine candidate,” Roger Connor, president of GSK vaccines, said in the announcement.  

“These immunogenicity and safety data confirm the important role that our adjuvant technologies play in vaccine development,” Connor continued.  

In March, SK bioscience signed an advance purchase agreement with the Korea Centers for Disease Control and Prevention (KDCA) for 10 million doses of SKYCovione.  

Additionally, the company will apply for emergency use listing to the World Health Organization (WHO) and authorizations at individual regulatory agencies globally. If authorized, SKYCovione could be available to the COVAX Facility for procurement and equitable allocation worldwide.  

Novavax Requests to Expand COVID-19 Vaccine Authorization in Great Britain  

Novavax recently submitted a request to the Medicines and Healthcare products Regulatory Agency (MHRA) in Great Britain to expand the authorization of its COVID-19 vaccine, Nuvaxovid, for adolescents aged 12–17.  

The company based its request on the totality of pre-clinical, clinical, and manufacturing-related (CMC) data. The submission includes clinical data from the ongoing pediatric expansion of PREVENT-19, which enrolled 2,247 adolescents across 73 sites in the United States.  

The study evaluated the safety, effectiveness, and efficacy of Nuvaxovid. Researchers found that the vaccine achieved its primary effectiveness endpoint in the trial and demonstrated 80% efficacy overall when the Delta variant was the predominant circulating strain in the US.  

Additionally, the vaccine was very well-tolerated, and serious adverse events were low. So far, India has granted emergency use authorization in this age range. And Novavax will continue to submit regulatory filings globally.  

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