Novavax’s Protein Subunit Vaccine Shows 89.3% Efficacy in Phase 3 UK Trial

January 28th, 2021 – Maryland-based Novavax announced today that its protein subunit vaccine met the primary endpoint in the Phase 3 trial conducted in the United Kingdom. According to the interim analysis from 62-subjects, NVX-CoV2373 demonstrated a vaccine efficacy of 89.3%. Besides, it has also registered positive results in a Phase 2b study conducted in South Africa. Novavax’s stocks have climbed 26% in after-hours trading since the announcement.

“With today’s results from our UK Phase 3 and South Africa Phase 2b clinical trials, we have now reported data on our COVID-19 vaccine from Phase 1, 2, and 3 trials involving over 20,000 participants,”. said Stanley C. Erck, President, and Chief Executive Officer of Novavax.

Remarkably, both the Phase 3 and Phase 2 studies include participants who have been infected with the COVID-19 variant strains that have emerged recently in the UK and South Africa, respectively. “NVX-CoV2373 is the first vaccine to demonstrate not only high clinical efficacy against COVID-19 but also significant clinical efficacy against both the rapidly emerging UK and South Africa variants,” mentioned Erck.

 

Phase 3 UK Trial

The Phase 3 study enrolled over 15,000 participants within the 18-84 year range. The “high risk” group, which constitutes the elderly over the age of 65, was around 27%. Among the 62 cases included in the interim analysis, six were in the vaccine group, and the remaining were in the placebo group.

The study was conducted at a time when the novel UK variant was rapidly spreading in the country.  PCR analysis confirmed that out of the 62 participants, 32 were infected with the UK variant, 24  with the non-variant, and six were unknown. Results showed that NVX-CoV2373 demonstrated a vaccine efficacy of 95.6% against the original COVID-19 strain and 85.6% against the UK variant.

“These are spectacular results, and we are very pleased to have helped Novavax with the development of this vaccine. The efficacy shown against the emerging variants is also extremely encouraging. This is an incredible achievement that will ensure we can protect individuals in the UK and the rest of the world from this virus,” said Clive Dix, Chair, UK Vaccine Taskforce.

With additional data, Novavax plans to approach regulators with the hopes of following the footsteps of Pfizer/BioNTech, Moderna, and AstraZeneca/Oxford vaccines, all of which bagged emergency approvals recently in the UK. While the Pfizer/BioNTech and Moderna vaccines registered close to 94% efficacy in Phase 3 trials, AstraZeneca’s vaccine was 62% effective.

 

Phase 2a South Africa Trial

In the smaller Phase 2a trial conducted in South Africa with 4,400 patients, NVX-CoV2373 was 60% effective in 94% of the study population that was HIV-negative. That number dropped to 49.4% if the HIV-positive population was included.

This trial was also conducted when the escape variant was widely circulating in South Africa. Among the 44 COVID-19 events reported, preliminary sequencing suggested that the variant was found in 25 out of 27 cases (92.6%). Although the efficacy seems comparatively weaker for the South African variant, experts suggest it is still significant.

“The 60% reduced risk against COVID-19 illness in vaccinated individuals in South Africans underscores the value of this vaccine to prevent illness from the highly worrisome variant currently circulating in South Africa, and which is spreading globally. This is the first COVID-19 vaccine for which we now have objective evidence that it protects against the variant dominating in South Africa,” says Professor Shabir Maddi, Executive Director of the Vaccines and Infectious Diseases Analytics Research Unit (VIDA) at Wits, and principal investigator in the Novavax COVID-19 vaccine trial in South Africa.

Nevertheless, Novavax has already commenced developing new constructs for variants in early January, with plans for a booster and/or combination bivalent vaccine in the future. The trials for those adjusted vaccines are planned for the second quarter of this year.

Related Article: Moderna Applies Two-Pronged Strategy to Fight against Coronavirus Variants

References
  1. https://ir.novavax.com/news-releases/news-release-details/novavax-covid-19-vaccine-demonstrates-893-efficacy-uk-phase-3
  2. https://www.reuters.com/article/us-health-coronavirus-vaccines-novavax/novavax-says-its-vaccine-is-89-3-effective-in-uk-trial-idUSKBN29X2W0

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