Today, Pfizer and BioNTech announced that their new mRNA-based coronavirus vaccine has achieved positive results in Phase 1/2 clinical trials. After two vaccinations, the neutralizing and antibody titer of the new coronavirus in the patients who received the 10?g and 30 sg doses of the vaccine reached 1.8 and 2.8 times the serum level of the recovered patients, respectively. The preliminary results of this clinical trial were also published in the preprinted website medRxiv.
The mRNA vaccine, called BNT162b1, is one of four mRNA vaccines currently being tested by the two companies in clinical trials. Pfizer and BioNTech plan to select the most promising of the four vaccines for large,global 2b/3 clinical trials, which could begin as early as this month. BioNTech has also entered into a cooperation agreement with Fosun Pharma to develop and promote these vaccines in China.
One of the important tools to combat the new crown outbreak is a safe and effective vaccine. According to the World Health Organization, BioNTech and Pfizer are among 17 vaccine development projects that are currently in clinical phase worldwide. The two companies screened a total of four candidate vaccines for clinical trials. They target the entire spike protein (spike protein) of the new coronavirus, or the receptor binding domain (RBD) on the stingprotein binding to the cell receptor. BNT162b1 is a mRNA vaccine that targets the sting protein RBD. It encodes a tripolymer RBD that folds according to natural conformation.
Different variants of the BNT162 new coronavirus vaccine
The phase 1/2 clinical trial was conducted simultaneously in the United States and Europe, with healthy volunteers between the ages of 18 and 55 receiving different doses of candidate vaccination. Some of them received two vaccinations 21 days apart, while others received only one vaccination.
Data from the 45 volunteers who were initially vaccinated showed that volunteers who received two vaccinations 21 days apart produced a strong immune response. Volunteers who received doses of 10 sg and 30 ?g reached a peak level of IgG antibodies bound with RBD in the blood on the 7th day after the second vaccination, with the geometric average of the antibodies (GMC) at 4813 units per milliliter, and 27,872 units/ml, respectively. They were 8 times and 46.3 times the average antibody level in 38 serum samples obtained from COVID-19 rehabilitation patients.
An evaluation of the neutralizing antibody titer of the newly crownvirus showed that the neutralized antibody geometric average titer (GMT) reached 168 and 267, respectively, among volunteers who received 10 ?g and 30 ?g doses. These values are 1.8 and 2.8 times the neutralizing antibody titer in the serum of the recovered person.
Interim immunogenicity data for BNT162b1
In terms of safety, adverse events mainly include pain and fever at the injection site. The occurrence of adverse events in volunteers who received doses of 10 ?g and 30 ?g showed dose correlation, mostly for temporary mild and moderate reactions. After receiving the second dose, 8.3% of the volunteers who received a dose of 10 ?g and 75.0% of the supporters who received a dose of 30 ?g developed a fever of more than 38 degrees Celsius. No serious adverse reactions were reported in the trial.
Interim data on safety and tolerance of BNT162b1
BioNTech and Pfizer will continue to observe the volunteers for at least six months to assess the vaccine’s safety and immune response, including the vaccine-induced T-cell response. CD4 and CD8-positive T cells also play an important role in the removal of viruses. Since it is not yet possible to predict the protective capacity of candidate vaccines for new coronavirus infections, the researchers will further explore the level of immune response to protective effects.
The role of the immune response caused by the virus in inhibiting the proliferation of the virus
BioNTech and Pfizer are also expanding the production capacity of the candidate vaccine, which, if successful and approved by regulators, estimates that it will be able to produce 100 million doses of the vaccine by the end of 2020 and could expand production to 1.2 billion by the end of 2021.
At present, a number of new coronavirus candidate vaccineist is about to enter the phase 3 clinical development phase, we look forward to hearing early good news of their clinical development, to overcome the new crown epidemic to bring a powerful weapon.