A Novavax vaccine for Covid-19 showed greater than 90% efficacy in Phase 3 testing, results that include protection against variants of the virus that have been circulating globally. With the data in hand, Novavax said it plans regulatory submissions with agencies throughout the world seeking emergency use authorization.
The results make Novavax the latest vaccine developer to post positive data in a large, pivotal study. The data readout has been highly anticipated, as the vaccine’s stability at standard refrigerator temperatures makes it easier to store and distribute in more parts of the world compared to the messenger RNA-based vaccines, which require ultra-freezing temperatures.
“This is a huge milestone for the company, and hopefully for the world of vaccination,” Novavax President and CEO Stanley Erck said during a Monday conference call. “We expect to bring our platform forward into people’s arms around the globe as soon as we can.”
The Novavax vaccine is protein-based, engineered from the genetic sequence of the first strain of SARS-CoV-2. The vaccine uses the company’s nanoparticle technology to generate antigen that is derived from the spike protein of the novel coronavirus. It also employs an adjuvant to boost the immune response. Use of the adjuvant means that less antigen is required per dose, allowing the Gaithersburg, Maryland-based company to stretch its manufacturing capacity further. Erck said that he expects manufacturing capacity to reach 100 million doses per month by the end of the third quarter of this year and 150 million doses per month by the end of the following quarter.
Novavax evaluated its vaccine in a placebo-controlled Phase 3 study enrolling nearly 30,000 patients in the U.S. and Mexico. Two thirds of the patients were randomly assigned to receive the vaccine given as two injections, 21 days apart; one-third was given a placebo. According to the preliminary results, the vaccine demonstrated 90.4% efficacy against infection from the novel coronavirus. Of the 77 cases observed in the study, 63 were in the placebo group and 14 were in the vaccine group. The cases observed in the vaccine group were classified as mild. The 10 moderate and four severe cases were in the placebo group.
Data collected for the study in early spring coincided with the emergence of several variants. Genetic sequencing data are available for 54 of the 77 reported cases. Of these cases, 38 were in the placebo group and six were in the vaccine group. Against variants of concern and variants of interest, which represented 82% of those cases, the vaccine’s efficacy was 93.2%.
“It shows that if you generate antibodies of a very high quality, they are able to impact variants of concern and variants of interest,” said Filip Dubovsky, executive vice president and chief medical officer of Novavax.
Novavax reported that its vaccine was generally well tolerated by patients. Common reactions included injection site pain and tenderness, as well as fatigue, headache, and muscle pain. Serious and severe side effects were low in number and balanced between both the vaccine and placebo groups.
There were six hospitalizations in the study, including one death. All of those cases were in the placebo group. Dubovsky said those cases were not included in the efficacy analysis because the patients were hospitalized and samples could not be evaluated in the central lab for the clinical trial, a requirement of the clinical trial protocol.
The Novavax study has since been expanded to include adolescents. Enrollment in this younger group is complete but data are not yet available.
Novavax conducted the Phase 3 test of its vaccine with support from the U.S. government, including the Biomedical Advanced Research and Development Authority, which is providing up to $1.74 billion under a Department of Defense agreement. The company plans to file for regulatory authorizations with the FDA and other global agencies in the third quarter after it completes the tests necessary to meet chemistry, manufacturing, and controls requirements. Some of those applications have already started as rolling submissions that allow a company to file data as they become available rather than all at once.
Photo by Novavax