AstraZeneca has restarted a phase III trial assessing its COVID-19 vaccine candidate AZD1222, after an unexplained potential illness led the Company to suspend the trial across the globe. After the United Kingdom (UK) committee concluded its investigations, the Medicines Health Regulatory Authority (MHRA) gave confirmation to proceed with the trial.

However, no additional medical information was revealed. According to AstraZeneca, the study investigators and enrolled subjects will be updated with the appropriate information. This will be revealed on global clinical registries. The Company will be coordinating with the other health authorities in order to check when the AZD1222 trial can resume in other parts of the world.

The vaccine candidate AZD1222 uses a weakened adenovirus (replication-deficient chimpanzee viral vector) in order to deliver severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protein. This elicits a vital protective immune response. The interim results from the phase 1/2 COV001 trial demonstrated that in healthy adults, the AZD1222 induced potent immune responses against SARS-CoV-2.

Regarding safety, transient local and systemic reactions were witnessed to be common. These included pain, chills, feverishness, muscle ache, malaise, headache, temporary injection site pain, and tenderness.

According to Pfizer and BioNTech, an amended protocol has been submitted to the Food and Drug Administration (FDA) in order to expand the recruitment of a phase III analysis evaluating their coronavirus vaccine candidate, BNT162b2 (a nucleoside-modified messenger RNA [modRNA] vaccine).

The companies are looking forward to incorporating novel study populations and also to expand their enrollment from 30,000 to 44,000 subjects. If approved, the study will recruit individuals as young as 16 years of age, and individuals with chronic, stable human immunodeficiency virus (HIV), hepatitis B or C infection.

The investigational vaccine BNT162b2 is responsible for encoding a SARS-CoV-2 full-length spike protein antigen. Based on the available data, BNT162b2 emerged as the strongest vaccine candidate displaying excellent overall tolerability and potent immune response.

By the end of October 2020, the companies will be still on track to have efficacy-related data. Fast Track designation was recently granted to the vaccine candidate. This permits expedited FDA review.