AstraZeneca Abandons Beta-Variant COVID-19 Vaccine AZD2816 Despite Advancement to Phase II/III Trials

Compiled by Aspirin

AstraZeneca's COVID-19 vaccine targeting the Beta variant entered Phase 2/3 clinical trials last year. As the Beta variant continued to drop in rankings among the most threatening variants, AstraZeneca ultimately decided to abandon this candidate vaccine, named AZD2816.

Another important reason is that there is no significant difference in immunogenicity between AZD2816 and Vaxzevria. Mene Pangalos, Executive Vice President of AstraZeneca's Biopharmaceuticals R&D, stated, "This means there is no need to switch from one vaccine to another, as changing vaccines at this stage is clearly not an easy task from both a manufacturing and capacity perspective."

Based on these two reasons, AstraZeneca will abandon this vaccine targeting the Beta variant and continue to advance its first-generation vaccine, Vaxzevria.

When the Beta variant was discovered in October 2020, it represented the most concerning SARS-CoV-2 variant at that time from the perspective of immune escape. The virus had undergone 10 mutations on the spike protein, quickly reducing the efficacy of the first-generation vaccines. It was reported that the effectiveness of the Novavax vaccine dropped from 89% in the UK to 49% in South Africa, where the Beta variant was dominant.

Given the minimal genetic differences between the Beta variant and the original SARS-CoV-2 virus, AstraZeneca responded by adapting its first-generation Vaxzevria vaccine. At the time, developing a Beta-specific vaccine was considered a prudent move within the industry. The Beta variant initially gained a foothold in South Africa and spread to some European countries during AstraZeneca's AZD2816 clinical trials. However, the subsequent global dominance of Delta and then Omicron significantly reduced the need for vaccines specifically targeting the once-concerning Beta variant.

AstraZeneca dosed the first participants in a 2/3-stage clinical trial in June 2021. The study eventually recruited more than 2,800 people to evaluate the efficacy of this vaccine and its first-generation product, Vaxzevria, under various different conditions. Participants included those who were unvaccinated as well as individuals previously vaccinated with Vaxzevria or an mRNA vaccine targeting COVID-19.

The rise and fall of AZD2816 provides a cautionary tale for Moderna and Pfizer. These two companies have recently just entered clinical development with vaccines specifically targeting Omicron. Although Omicron is far more prevalent than any previous variant, the speed with which it replaced Delta, and the fact that it differs significantly from previously dominant variants, suggests that any vaccine targeting a specific form of the SARS-CoV-2 spike protein may become obsolete before reaching the market.

AstraZeneca disclosed the termination of AZD2816 in its quarterly report, while also revealing the removal of a series of early-stage projects from its pipeline. The large pharmaceutical company disclosed the recent sale of its cholesterol drug MEDI5884 to Regio Biosciences, as well as the divestment of an antibody used to prevent pneumonia caused by Staphylococcus aureus. Both projects were in Phase II clinical trials. Another Phase II project, the solid tumor candidate drug AZD2811, along with three Phase I projects, were all successful, including the inhaled JAK inhibitor AZD0449 for asthma patients.

Reference Article: AstraZeneca dumps late-phase, next-gen COVID-19 vaccine, calling time on a beta player in an omicron world